Crozier,
Not too sure of your question from the link posted.
The training issue is off the track. A TRTO will have authorization to perform maneuvers required for training by the regulator, in the absence of a training device. That authorization is completely unrelated from what an operational crew is authorized to do, as per the AFM. The relevant regulator will impose conditions on the TRTO as to how perform, in this case, partial flap landings for training and evaluation.
It's Cat C for straight-in approaches, Cat D for circling. This oddity has to do with the final approach speed for flaps 45 on straight-in and circling speeds with flaps 30 for circling. Yes, a bit unusual that it falls out this way.
The fact that that most KASE landings are flown "straight in" visually is irrelevant to the discussion. The fact that the final approach descent gradient exceeds 400 ft/nm means it is a "circling" approach, not how the plane is aligned with the runway. Some TERPS/PANS-OPS study is in order, perhaps.