IMO, do 100%. Why? As per the OC CO, assuming you can't get a PFD or even if you want one based on age, a PIF balance can increase your odds in getting a GW accepted to change wording on CR, lates, etc.
A CA, in our experience anyway, offered a settlement and we accepted (years ago before this forum). We paid 70% I think and that was that. But that CA sold the balance (30%) to another CA and on it went. Also a PIF CA is easier to remove than a settled CA, again assuming PFD doesn't work.