i think of positional sparring/drilling differently than regular rolling.
in positional sparring, i use that time to open my game up and work on stuff i normally would not do or stuff i'd like to implement. so if someone is ripe for the picking, i won't take it cuz i don't stand to gain anything from going to the things i do exceptionally well. i'll try and set up something else and see if it ellicits the response i want.
during sparring, if an opportunity to use my A game is presented to me, i take it...especially against folks who match up with me skill-wise cuz i need to know if it works against someone applying their A game defense. if opportunities arise to use new stuff, i'll do that too regardless of where i might end up after the exchange