OK, I am tired, but I am not sure that I am making sense of the GPU classes small print and classes that are eligible or not for upgrades. Can someone tell me when going from LHR-SFO-LHR what are the classses that I can use GPU on?
Eligible flights says:
They can be used on all paid, published fares except:
S, T, K, L, G and N fare classes, for upgrades from United Economy® to the next higher cabin on most long-haul international flights
See the upgrade regions chart for full details on upgrade eligibility and fare restrictions.
This says:
For regions with a *, Global Premier Upgrades are not available on flights booked in fare classes Z, P, S, T, K, L, G or N. (LHR falls in this region)
So, it seems to me that if the class is Z, P, S, T, K, L, G or N, then I cannot use GPU, but any other classes I will be ok to apply a GPU with Y, B, M being the favourites due to its clearing because "Premier® 1K® members on M fares are available on all flights that are eligible for Complimentary Premier Upgrades."
I would be grateful for a sanity check.