This sounds exactly like me, except I do it on purpose because I get bored of following proper BRM...which is totally opposite of what I preach.
Actually what I do is start of with a set amount like $50-$100, then I'll follow good BRM and build it up slowly. But once I hit a goal BR, say $200, then I'll loosen up and play games out of my BR range with my profits. Not ridiculous stakes, but maybe one or two levels higher. Like if Im playing $5 SNGs, I'll jump to $10 SNGs.
Of course my goal is to make a win and make a huge jump in profits, but Im only putting what I've earned at risk. If I drop to my original starting BR, I have no problem with starting building it again.
I'd also like to add that I have no problems playing out of my BR range because Im only playing for fun and entertainment. I dont play a means of income or anything. If I make a big BR int he process, great. If not, I have not problems with starting from ground zero.