My company only has the standard 'Captain PF for Cat ll operations'.
I see no logic for differentiating between the PF and PNF.
It only serves to keep the satisfaction of using ones skills from perfectly able FO's and protects/hides sub-standard FO's.
An on the ball FO should be able to see where he may be close to his limits and offer control to the captain
A captain can at anytime takeover the duties of PF anyway with the line "If it's going to get broke, let me break it!"