Is there any advantage (lower rate) when bidding for two or more nights, instead of just one?
I have used PL for many years, but almost always bid just for one night.
Bidding for 2 nights this week in NYC, not sure what to expect.
The only advantage to bidding for two nights vs. two one night stays is that the fee will be very slightly lower per night. During periods of high occupancy in large cities that should be weighed against a single hotel providing access to inventory for more than one night. The difference in a one night stay vs. a two night stay is so negligible, I wouldn't even consider it.
You can always check Express Deals to see the difference in your situation.