corporate-wage-slave

So to clarify, you should assume you only get TPs and Avios relevant whatever cash you put into the initial revenue ticket. If you add more cash, be it POUG, fare difference upgrade or AUP, you get more TPs and Avios. This includes revenue tickets where you also reduced the cash component with Avios part pay.

A UuA should leave you with the TPs and Avios of the initial revenue ticket, piling on a POUG (this is a relatively new development) or AUP (not at all new) won't give you the right to any more TPs or Avios. You can't do a fare difference after a UuA, but you can remove a UuA at least 24 hours from departure, get your Avios back, and then do a fare difference (and thus get extra TPs and Avios). This is worth bearing in mind since it may be more efficient to do this instead of a TP run or whatnot if running close to your year end. If you accept a POUG then there is no refund of the POUG so that's a dead end for this line of enquiry.

If you started with a redemption / Avios ticket, no matter what you add on, you get nothing in terms of TPs and Avios, It makes no difference if you AUP or POUG, and fare difference doesn't apply. Adding more cash to reduce the Avios needed makes no difference either. You can't UuA a ticket which started as a redemption, but if availability comes up you can alter an existing booking to go up a cabin or two or three.

All this assuming that BA's creaking IT holds up, of course, which is what it is, so we don't really need data points.