score:3
I was at the Singapore airport today and was allowed the entry at the Ambassador Transit Lounge in terminal 2 with no issues whatsoever. The guy at the reception did not even bother checking the boarding pass and He told me that they always take people in holding the PP.
I don't know about the other lounges but you can always go to 'The Haven' arrivals lounge if you are denied entry.
Upvote:2
According to Review: βThe Havenβ Arrivals Lounge β Singapore T3
as a Priority Pass holder:
Priority Pass, LoungeKey, LoungePass and DragonPass all get 3 hours access, including access to shower facilities, but not the nap rooms.
and
Priority Pass will get 20% off nap room rates (others vary, call for more information).
The link mentions how to get to this location if you are arriving on a flight - thus implying you can use it when you arrive.