Where a PR is really valuable is when you don't have any remaining x days to put it over, it goes as a full PB in your bank.

If you still have xdays, it changes when you are usable by the company.

In practical terms that hasn't been very useful to me, they always found a way to use me.

But I used to do a lot of one day GS. Getting paid over guarantee plus two PB in the bank was awesome.