If i am working a mat...I'll break it up, flipping a section about 4ft diameter at a time, working the whole mat. The initial flip...let it fall all the way down, un-impeded . Yo-yo it up to the bottom of the mat...let it fall again. I'll yo-yo it 2-4 times depending on how confident I am of the pitch or of the spot. After 2-4 lifts/drops, crank up and make a new pitch. At least half of the time, they hit on that initial drop....I would say 95% of the time they hit within the first 3-4drops. To me, it's about percentages, so I think in the long run you are better making a new pitch than continuing to yo-yo the bait 5-6-7-10 times trying to elicit a bite from the 5% of fish that are non-committal.
If I'm flipping a stretch of reed heads or other standing vegetation, I'm typically moving a little faster and will rarely pitch to the exact spot twice. However, if there is an obvious piece of structure that looks good, I'll pitch to it repeatedly from different angles, trying to elicit a strike.