The BTTF trilogy DVD release explained all of the "plot holes" fans have brought up about the movies. Specifically regarding old Biff returning to the future, the future WAS changed around Marty and Doc while they were there.. You'll notice that Biff came back to the future JUST AFTER Doc managed to grab Jennifer and asked Marty to help him. So between that time the timeline could have changed and there would be somebody completely different living in that house and neither of them would have noticed the difference.
It makes sense, even if it is reaching...
Originally Posted by TomPravetz
This is the internet and you made a typo. Therefore, I won this argument. My opinion is now fact.