I am afraid your understanding is incorrect. We do not say Tto meogeosseo (또 먹었어) as in “you’ve eaten it too”. Tto meogeosseo (또 먹었어) means “you ate again” and it implies the speaker’s surprise or dissatisfaction with it. For example, a parent’s boy likes sweets too much, so s/he told him to stop eating sweets for the time being. But when the parent found that he ate sweets again, s/he might say, Tto meogeosseo! (또 먹었어!) In general, the verb “hada (하다)” does not replace action verbs but only when a verb consists of a noun and “hada”, “hada” can replace the verb. 나 어제 공부했어. (I studied yesterday.) 나도 했어. (I did too.) We use "Geuraesseo” as in (B)’s reply. (A) I couldn’t sleep all night. (B) Did you? In the event that you just remembered that she had eaten it before, you can use "Geuraesseo!" but you should say “Mat za (맞아) first. If you say "Geuraesseo!" alone, it would sound very unnatural. "tto geuraesseo!"’s usage is similar to that of “Tto meogeosseo!”, which means “you did it again!”. So, it doesn’t make a sense at all if you say “Tto meogeosseo!” when you just remembered that she had eaten it before.