In the manga we only see Usagi transform into Eternal Sailor Moon (via calling out her transformation phrase "on screen") three times - in Stars 1, Stars 2, and Stars 5.
Here are these scenes from the original serialized run in Nakayoshi:
We see that in Stars 1, Usagi uses "ムーン・エターナル・パワー・メイクアップ!" ("Moon Eternal Power Makeup!") to transform. In Stars 2, however, her transformation phrase has been slightly altered to "ムーン・エターナル!! メイク・アッップ!!" ("Moon Eternal!! Make-Up!!") . In Stars 5, she uses this same phrase, only with one less exclamation mark after "Eternal."
Now, the dropping of the "Power" is curious enough in itself, but just as curious is Naoko's suddenly switching from using the standard katakana approximation of makeup (メイクアップ meikuappu), which, from what I can tell, is what she'd always used before, to this new approximation (メイク・アッップ). Since she repeats this rendering in Stars 5 and did not correct it in any of the compilation releases, it doesn't seem to be an error.
It's also not the only example of orthographic oddities in Stars. Also taken from the original serialized run in Nakayoshi:
In the page showing the Sailor Starlights calling out their transformation phrases in Stars 2, we see that Naoko uses the standard katakana rendering of makeup (メイクアップ). (In fact, if I'm not mistaken, she only uses her weird alternate rendering with the double sokuon for Eternal Sailor Moon's transformation phrases). However, the "Power" part of their transformation phrases are written with a seemingly superfluous sokuon, as: パワーッ. Similarly, when Mars and Venus call out their "Crystal Power" transformation phrases in Stars 3, two seemingly superfluous sokuons are added to the end of the "Power" part, as: パワーッッ. Can someone explain these orthographic oddities? Might there be some stylistic rationale behind Naoko suddenly adding all these extra sokuons everywhere? Or do you think she (and her editors) just got super tired during the Stars arc and forgot how to spell?
(And, while we're on the subject of Mars's, Venus's, and everyone else's transformation phrases, how lame is it they didn't get new ones given they got new uniforms? They didn't even get new powers. Jeez. No new transformation phrases, no new attacks, and all forced to wear identical, albeit color-coded, uniforms with ugly bubble sleeves, only to be quickly and unceremoniously dispatched by Galaxia and her minions? Naoko must have really hated the Inners and Outers by the end of the manga's run to do them so dirty!)
Anyway, back to Eternal Sailor Moon.
From the tankoubon release:
Here we see that, for the original compilation release of the manga, Naoko completely changed Eternal Sailor Moon's transformation phrase in Stars 1 (along with drawing a completely new page to go with it), to "シルバー・ムーン・クリスタル・パワー・メイク・アップ!!" ("Silver Moon Crystal Power Make-Up!!"). In Stars 2 and Stars 5, the double sokuon rendering of "Make-Up" returns ("シルバー・ムーン・クリスタル・パワー・メイク・アッップ!!"), so Naoko seems pretty married to that little oddity for some reason.
Now, "Silver Moon Crystal Power Make-Up!!" is quite a mouthful compared to "Moon Eternal (Power) Make-Up!!" However, I think it's what Naoko originally intended Eternal Sailor Moon's transformation phrase to be. At the beginning of Dream 11, Eternal Sailor Moon starts off the standard "it's-the-final-battle-so-let's-all-combine-our-powers" thing by saying "Silver Moon Crystal Power," which prompts the others to call out their "base form" (i.e. sans "Make-Up") transformation phrases ("Venus Crystal Power," "Pluto Crystal Power", etc). Therefore it makes sense that "Silver Moon Crystal Power Make-Up!!" would be ESM's transformation phrase. Why Naoko then used "Moon Eternal Power Makeup" and then "Moon Eternal!! Make-Up!!" is beyond me.
But also beyond me is what Naoko did for the revised edition and re-revised/perfect/eternal edition releases:
That's right. In Stars 1 Usagi has gone from using "ムーン・エターナル・パワー・メイクアップ!" ("Moon Eternal Power Makeup!") in the serialized release, to "シルバー・ムーン・クリスタル・パワー・メイク・アップ!!" ("Silver Moon Crystal Power Make-Up!!") for the first compilation release, to "ムーン・エターナル!! メイク・アップ!" ("Moon Eternal!! Make-Up!") for the (re-)revised release(s). Yet, in Stars 2 (and, I'm guessing, Stars 5, though I wasn't able to pull up scans of that chapter), she's back to using "Silver Moon Crystal Power Makeup!!", this time rendered, still with the double sokuon, but without the interpunct, as: "シルバー・ムーン・クリスタル・パワー・メイクアッップ!!"
So... What gives? What's up with the constant changes back and forth with Eternal Sailor Moon's transformation phrase? What's up with all the orthographic oddities with superfluous sokuons and appearing and disappearing interpuncts? Could there be any artistic explanation, or is it just sloppy editing madness?
In any case... I never want to see a diehard manga fan criticize the original English dub for its inconsistent attack and transformation phrases ever again.
Here are these scenes from the original serialized run in Nakayoshi:

We see that in Stars 1, Usagi uses "ムーン・エターナル・パワー・メイクアップ!" ("Moon Eternal Power Makeup!") to transform. In Stars 2, however, her transformation phrase has been slightly altered to "ムーン・エターナル!! メイク・アッップ!!" ("Moon Eternal!! Make-Up!!") . In Stars 5, she uses this same phrase, only with one less exclamation mark after "Eternal."
Now, the dropping of the "Power" is curious enough in itself, but just as curious is Naoko's suddenly switching from using the standard katakana approximation of makeup (メイクアップ meikuappu), which, from what I can tell, is what she'd always used before, to this new approximation (メイク・アッップ). Since she repeats this rendering in Stars 5 and did not correct it in any of the compilation releases, it doesn't seem to be an error.
It's also not the only example of orthographic oddities in Stars. Also taken from the original serialized run in Nakayoshi:

In the page showing the Sailor Starlights calling out their transformation phrases in Stars 2, we see that Naoko uses the standard katakana rendering of makeup (メイクアップ). (In fact, if I'm not mistaken, she only uses her weird alternate rendering with the double sokuon for Eternal Sailor Moon's transformation phrases). However, the "Power" part of their transformation phrases are written with a seemingly superfluous sokuon, as: パワーッ. Similarly, when Mars and Venus call out their "Crystal Power" transformation phrases in Stars 3, two seemingly superfluous sokuons are added to the end of the "Power" part, as: パワーッッ. Can someone explain these orthographic oddities? Might there be some stylistic rationale behind Naoko suddenly adding all these extra sokuons everywhere? Or do you think she (and her editors) just got super tired during the Stars arc and forgot how to spell?
(And, while we're on the subject of Mars's, Venus's, and everyone else's transformation phrases, how lame is it they didn't get new ones given they got new uniforms? They didn't even get new powers. Jeez. No new transformation phrases, no new attacks, and all forced to wear identical, albeit color-coded, uniforms with ugly bubble sleeves, only to be quickly and unceremoniously dispatched by Galaxia and her minions? Naoko must have really hated the Inners and Outers by the end of the manga's run to do them so dirty!)
Anyway, back to Eternal Sailor Moon.
From the tankoubon release:

Here we see that, for the original compilation release of the manga, Naoko completely changed Eternal Sailor Moon's transformation phrase in Stars 1 (along with drawing a completely new page to go with it), to "シルバー・ムーン・クリスタル・パワー・メイク・アップ!!" ("Silver Moon Crystal Power Make-Up!!"). In Stars 2 and Stars 5, the double sokuon rendering of "Make-Up" returns ("シルバー・ムーン・クリスタル・パワー・メイク・アッップ!!"), so Naoko seems pretty married to that little oddity for some reason.
Now, "Silver Moon Crystal Power Make-Up!!" is quite a mouthful compared to "Moon Eternal (Power) Make-Up!!" However, I think it's what Naoko originally intended Eternal Sailor Moon's transformation phrase to be. At the beginning of Dream 11, Eternal Sailor Moon starts off the standard "it's-the-final-battle-so-let's-all-combine-our-powers" thing by saying "Silver Moon Crystal Power," which prompts the others to call out their "base form" (i.e. sans "Make-Up") transformation phrases ("Venus Crystal Power," "Pluto Crystal Power", etc). Therefore it makes sense that "Silver Moon Crystal Power Make-Up!!" would be ESM's transformation phrase. Why Naoko then used "Moon Eternal Power Makeup" and then "Moon Eternal!! Make-Up!!" is beyond me.
But also beyond me is what Naoko did for the revised edition and re-revised/perfect/eternal edition releases:

That's right. In Stars 1 Usagi has gone from using "ムーン・エターナル・パワー・メイクアップ!" ("Moon Eternal Power Makeup!") in the serialized release, to "シルバー・ムーン・クリスタル・パワー・メイク・アップ!!" ("Silver Moon Crystal Power Make-Up!!") for the first compilation release, to "ムーン・エターナル!! メイク・アップ!" ("Moon Eternal!! Make-Up!") for the (re-)revised release(s). Yet, in Stars 2 (and, I'm guessing, Stars 5, though I wasn't able to pull up scans of that chapter), she's back to using "Silver Moon Crystal Power Makeup!!", this time rendered, still with the double sokuon, but without the interpunct, as: "シルバー・ムーン・クリスタル・パワー・メイクアッップ!!"
So... What gives? What's up with the constant changes back and forth with Eternal Sailor Moon's transformation phrase? What's up with all the orthographic oddities with superfluous sokuons and appearing and disappearing interpuncts? Could there be any artistic explanation, or is it just sloppy editing madness?
In any case... I never want to see a diehard manga fan criticize the original English dub for its inconsistent attack and transformation phrases ever again.