I guess it also depends on what MC fares you’re comparing it to. I was booked in MC with them at a similar fare as their eventual post-refund fare, and then we decided we wanted to switch to the nonstop on the return. For some reason that was a $30 change for them through the app, but when I called (my ticket was locked out of self service changes for some reason) I was quoted a >$500 fare difference. I’d also previously seen PS as a change option for them at what at the time felt like a fairly reasonable difference (don’t remember the number) but not something they were interested in. At that point I contemplated just cancelling and rebooking in MC outbound and PS return, but that was still very expensive, but the next week I saw the MC for the outbound had dropped in price. I was about to go ahead with booking that, but then at the checkout summary it offered me the PS upsell for the outbound as well and IIRC it was a little over $200 so I ended up booking that.