Ugh, I forgot about that. Yes, that’s correct, so that would be something to consider. Still, for OP: I would absolutely not recommend booking roundtrip tickets that include partner segments, unless you’re using the Excursionist Perk (which, as discussed, you’re not), even if there’s a mileage discount, if there is a reasonable chance of needing to make a change (which, in your case, I think there is). You are unlikely to be able to change one direction without affecting the other, because UA is likely to need fresh inventory in both directions, even the one you’re not changing. Also, by booking separate one-ways, you can lock in the prices individually rather than having to wait until both the outbound and return show prices that you like simultaneously.