what was up with the repairman?

I have a theory that really works, but is very complicated...

Basically, in the far future, Jacob (Lou's son), who is very rich from dad's money, either "invents" the time machine (to prevent a paradox) or hires the guy who does.

Chevy Chase's repairman character(inventor of the time machine ?) is pretty much only hired, because Jacob remembered him from when he went back to the 80's.

Jacob gives the Repairman specific instructions of what he is (and isn't) allowed to say and do when he first meets the 4 when repairing the machine in the 80's (perhaps the only time that the machine ever needs to be repaired).

So basically, future-Jacob is meticulously laying down the groundwork for how and why the time machine is even built into a hot tub and why Chevy chase's character has to be the repairman (even tho Jacob hates him) with the intent of preventing any (more) time paradoxes.

It was just typical Chevy Chase Charity: write in a character he can play so he can have money for more alcohol/drugs.

Been that way since the 90's for him; first with movies written for him, and then with only bit parts. Those who grew up watching him and later working in the industry just giving back to one of their heroes, supporting him in his golden/no career years (90's on).

I was hoping it would turn out he was just a regular repairman. And it would turn out that he just spoke strangely, which made them think he was speaking in metaphors given their situation, but really he was just talking about repairing the hot tub. And then when he mentioned what went wrong with the hot tub, they would realize that was the reason it turned into a time machine. And he'd be like "time machine? What the hell are you talking about?"

I think that would've been funny :-) But no, I guess he really was some part of the sci-fi story.