Certainly not my experience with an advancer, nice improvement in the bottom end, still really smooth, I love the way the bike can pull from 30mph in 6th gear fully loaded. I can only think yours is slightly out of tolerance?
Mines an Ivans Full Monty job with ported carb mounts & airbox lid mod & pipercross, bikes a rocket & smooth as silk at all rev ranges once I'd had a play with the mixture screws, which if set as Ivan recommends, it's way too rich, maybe I should have gone with my first gut instinct & drilled only 1 hole in each carb, she's runs mint with minimal vibes now.
So me being me, I like to try new stuff, so I bought the CCDF rotor, seemed the best around on sale & seller is the actual manufacturer, part was listed as early R1 fitment, so a message to seller confirmed it can be used on the Fazer 1000 motor ... before fitting I placed it over the OEM rotor & it's identical apart from the centre hole slot is approx a 2mm difference from the OEM, I did consider filling the OEM rotor, but decided against it in the end. New 4 degree rotor needed a tiny bit of file attention to a few bits of flashing around the edges on the pick up tips, as it's clearly been stamped from a sheet of metal & not laser cut as I thought, seller stated it's a magnetic stainless rotor, it is indeed magnetic, tested before fitting, rotor also needed a tiny bit of filing on the centre hole slot as too tight a fit on the crank end ... I've given it a good 50mile blast yesterday, can defo feel the difference in grunt out of corners etc from low rpm's but it just feels too rough at low revs for my liking, ie) filtering in traffic etc is not good & too jerky, bit like an injected bike on a factory fuel map, very much like my 5th Gen VFR800fi, so after sleeping on it, OEM rotor is going back in.
May work better on a stock motor, clearly my motor aint too happy with it at low rpm's.
The old saying applies on this occasion, "If it aint broke, don't fix it".
You win some, you lose some.