Ok, not to be too much of a geek about this, but I think they are off on the whole "diet coke" thing in this show. The kids are supposed to be 36 right? Which means they were born (assuming this is reasonably real time), in 1980 or so, right? 1980 plus 36 years equals 2016. Maybe 1979? So, this show with mom at lunch would be either 1978 or 1979 most likely. And, what do you know, they are ordering a diet coke. Except diet coke wasn't marketed until July 1982. So, there you go. Not possible. LOL. It was bugging me that it was out of sequence with real events of that time. I don't remember being "obsessed" with diet vs. non-diet drinks when I was in high school or even college which got me thinking that there must not have been diet drinks (other than Tab, remember that?) during that time. And, sure enough I was right.
ETA: This also fits with the idea that they were conceived during the Super Bowl, in January 1979. So born in late 1979. Impossible for that to have been diet coke.