Well he wrote it a bit complicated. Let me rephrase it in more direct manner.
No, the affection is "character ID" bound, not "character bound". Meaning once you max affection on a character, it doesnt matter how many copies of that character you max the affection later on, you wont get another Flower Gem.
Each person maxed grants 1 Fgem the first time you max her, any subsequently affection maxed copies of her will not give you another FGem.