Yep. Apparently running a Business on a lot means that any Household members on the lot when money is earned get that money counted in towards their lifetime earniings.
My apologies, but i guess i didn't make it clear. The teens went to their Family's Owned Community Lot to run that turnstyle business. The teen's Father was the owner of the lot but he was not present there, nor was their mother, nor were the two younger sibling kids. Yet the kids got a memory of earning 50,000 even tho the teens brought home 500,000
I'll have to set up some experiments to see if it's that 'aging up a sim using the Elixer at the Community Lot' or if it's there's a 'threshold of money earned' that causes it.