If you only want a 4n/5 day UPH, and you are staying for 5 nights/6 days, you will have to book 2 reservations. Either the 1st night or the last night, as single reservations/no passes and
then either the first 4/last 4 nights with the UPH passes.
The UPH passes are what some still call LOS passes (Length of
stay). They are tied to the number of nights you stay.
The 2 room reservations would be 1nt/None Plan (no passes)
and the continuing reservation (4nt/5day) Plan nights (with
passes)