Questions keep coming. Here's some I will answer and post on Primer Universe:
1. Did Aaron both cause and solve the problem at the party?
It does seem that Aaron is easily bored. Inviting Will's cousin leads to him being arrested and out of the way. (Perhaps Abe was afraid of him? If Aaron felt this was an error, then likely he would repeat this day and not invite Will. Really, where would half of Primer be without the angry ex at the party? So, Aaron sets the stage for trouble, then becomes the hero. In the last revision, he invites Abe to go with him. In theory of the film, it is likely that Abe doesn't trust Aaron in his desire to redo the party, so Abe goes back and convinces Rachel not to go to the party. This would fit the need for Aaron to explain why he should make sure Rachel attends the last revision. Aaron says Rachel only attends because Abe was going. But we know from Aaron's past, that Abe didn't go.
2. Is it possible to do the party twenty times over?
Only if you can convince your former self not to go, allowing the new you to take his place. On some level this works for Aaron(3). It could be because he learned how necessary this is after confronting and failing to get Aaron(2) back in the box.
3. I need some help with the timeline.