Prior to the II upsize charges, I thought any of the resorts that have 1BR units could request in exchange a 2BR unit at any resort that doesn't have 1BR's, but Custom House was the only one where a 1BR deposit is equal in trade power to a 2BR deposit.
Since the II upsize charges, it looks like the same is still true for Custom House 1BR exchanges and they won't be subject to an upsize fee. For all the other non-Custom House 1BR's, there's still the same ability to request a 2BR but the upsize fees will be charged.
Here's a 2018 thread:
Possible to trade Custom House 1BR for 2BR ski week?