It seems that some blokes at certain Yamaha dealers can actually adjust the fuel mapping of the bike. Is that not maybe what the guy did who serviced your bike ?
I can't stop enjoying the power and smoothness of my bike. I bought it on 2500km from a friend with a few mods including Scorpion pipes and DNA stage 2 filter and air inlet.
Just today when I told him about your experience with Kev's mod and O2 controller, my friend told me that my bike was mapped by Yamaha to match the DNA filter and specific pipes when he bought it new. I don't know much detail about the tuning (apart from what I've read on the forum), but it makes sense why my bike is so powerful and smooth from below 1500 revs right to redline.
When cold it idles at 1400-1500 rpm but drops to a steady 1200 rpm when hot with enough power to idle in first gear at under 1400 rpm.