Sounds like you don't COmpletely understand how the upgrade program works. It most definitely could be a trivial amount if the customer is on EWR-LAX as part of a COnnection, depending on how their fare class maps up.

I can't find a good example involving EWR-LAX, but I'm sure there is one out there. But here's one with EWR-PDX:

If you buy a U fare XXX-EWR-PDX (say DCA-EWR-PDX for $476 RT all in). As a Platinum, the lowest fare to COnfirm into F at time of booking in that market is more than $1,100 more (a B fare for $1,608 RT all in).

At checkin, it's possible that you will get offered a "fare difference buy-up" for your EWR-PDX segment for the difference between U and M on that segment. The difference between U and M on EWR-PDX is $130 RT, or $65 one way. So it's possible you'll get an upgrade offer for $65 on that one. Hence the 'tens of dollars' references we COntinue to hear.

There have even been examples of upgrade offers for less than $10.