Mxsmanic wrote:
Jim Logajan writes:

His new portable would almost certainly use WAAS when available and
would not be off by 500 ft.

WAAS is independent of GPS. It's one of many GPS augmentation schemes.

WAAS cannot simultaneously be independent of GPS and an augmentation of it.
Only the second of your two quoted sentences is accurate in any useful way.

While your conclusion that he should use the altimeter set to the nearest
station setting was correct, the rationale leading up to it was based on an
invalid premise.