Was talking to a guitar/bass tech the other day (he appears to be good at set-up work) about trying my hand at installing a custom Willis-type ramp between the stock pups of my Cirrus 4. So I tell him that I'll first raise the pups so that when the ramp is flush with the pups, it'll be close to the strings (right now the pups are probably around 3/8" away from strings - at that relatively low height I'm guessing a ramp won't mean much). But he cautions me that raising the pups might cause minor intonation problems, saying the magnetic pole pieces can decrease the plucked string's vibrating frequency - the plucked string will then produce a slightly lower pitch than desired. He says because my Cirrus is active, the problem will be minimal but still an issue. I'd never heard of pup height affecting intonation. Is this right?