Upload & Sell: On
A couple things come to mind.
1. You've got an EC of + .3 stop dialed in. This is telling your camera that you are asking it to increase exposure above what it would normally recommend. Given that you are WO on the lens and have a 1/200 shutter limit, then it has no choice but to raise ISO (auto ISO is a feature I wish Canon would better embrace as an option, btw. I enjoyed it in my D70s.). If you don't want the bump in noise, don't ask it to raise the exposure. I realize that .3 stop isn't much, but the concept is the point here.
If you weren't at max aperture and a limit set for your shutter, then your camera would let more light in via one of those two methods and not raise your ISO, but when it's only remaining option is to raise the ISO, then that's what it's gonna do.
Essentially this boils down to strategy and approach at how you want to proceed. If you were to change your max ISO to say 1000 or 1600, then you would keep the noise in check, but might run into underexposure. Given your propensity for PP, I wouldn't be overly concerned by such possible underexposure as I would bank money that you could deal with that just fine in PP better than the camera's higher ISO does.
2. With your shutter speed limit set @ 1/200 you are restricting yourself a bit somewhat. Not sure if this is over concern at camera shake or subject movement, but maybe moving that down to 1/160 or 1/125 could help with keeping the uber-iso at bay. In this particular instance, with a 55mm FL you've got some latitude regarding camera shake. Additionally, if you happen to be using IS glass, it becomes even less of an issue. Subject movement of course is a different matter regarding shutter speed selection.
From that, I'd probably recommend changing your EC from +.3 to -.3, max your ISO @ 1000, 1250 or 1600, and drop your shutter limit to 1/160. Nothing too radical in any one area, but the combination of things would put your ISO a stop slower based on the 2/3 change at EC and the 1/3 change at shutter limit. should help keep you from unnecessarily going into uber-iso while shooting in "spontaneity mode" ... even if you do run into some mild underexposure on occasion. You'll "play with it" and find your groove on how you want to structure things for your shooting style, but that's my take on it atm.