Exactly. Instead of an offer to make the upgrade from an already purchased fare that at least goes "well, hey, dude already gave us some money so we should account for that when we offer an upgrade price", I am penalized to make an upgrade (charged more to make an upgrade than if I just booked a D1 ticket), compared to a cancel and rebook (cash price OR miles price).

Yes, in the world of FT where we know all the ins and outs and tricks and nuances "duh, just cancel and rebook if Delta's being dumb about pricing your upgrade" is obvious, but how obvious is it to people who don't live in our bubble?

I'm sure there's some amazing "revenue management is smarter than you are to price an upgrade from PS to D! more than the actual D1 ticket if you just bought a ticket" reason for this (I mean, it IS SkyPesos, you have to be dumb as a post to throw almost 400k miles at something you can get cheaper elsewhere, maybe Delta just wants rubes off the turnip truck).