UPDATE: Today I went to my local Specsavers for a third opinion/test, and guess what - it’s almost exactly like the original (less severe) one!
So to put them all side-by-side, here is the first one 7 or so months ago @ Amplifon:
Here is the Costco one two months ago:
And here is today’s one @ Specsavers, done with a brand new booth & equipment:
What was really cool was despite this check supposedly being a “quick” free 15 minute one, the audiologist there was so intrigued by my reason for coming in and bringing a Philips hearing aid with me (which they don’t sell there) that she fired up HearSuite on her system and re-programmed my aid - complete with REM adjustment - to fit against the new audiogram so I can actually try it out for a couple of weeks until my next Costco appointment! Think it must have gone for 40 mins in the end, but she didn’t mind at all.
Anyway, it seems I have some legitimate questions to ask my Costco audiologist next time I see her…