There is no time frame applicable.

Yes, Medusa had that costume in FF 132. That was more than a hundred issues before the FF's 'negative' costumes appeared... But it doesn't matter!

It's a commission. It's fun. It looks great. Trying to apply some weird rules of continuity actively doesn't make sense, as it's purely down to the person who commissioned the work ,as already pointed out, and furthermore, sucks all the fun out of it.

I believe JB summed this up in a four-letter word that begins with S.