That premise went out the window pretty early or never existed in the first place... i mean you get a special render for jill in the game showing her boobs even BEFORE you really met her in the game. I dont even think that this is a "rule" DPC made or if so he doesnt act like it even exists anymore. There are so many examples where the special renders took it further than the game at the point... full on nudes for Jill or Bella for example (and together too), even though it sure does take some time to get to see them fully nude in the game, via special render you get so see them first. And same goes for many more. Its the reason why i dont watch the special renders anymore and dont care for them. They dont give me anything, and yeah they kinda ruin the immersion too i guess, cause they are showing the girls way out of character.The premise was that special renders wouldn't take it further than what had already happened ingame. Vaginal for Sally and Heather is taking it further.
I get it that those are more "fanservice" and kinda fun to make for DPC. But nah, i dont think there is any "rule" that those special renders shouldnt take it further like the game does, cause they clearly GO way further for most characters. And to think about, that is the whole point for those special renders? To show something that the game will not give you otherwise... so of course they take it further.
Heck there is even a shuffle picture with cathy and jade both sucking the MCs dick in episode 1 way before you met them... never happened ingame and iam pretty sure it never will. So no i dont think this "premise" is existing.