And that right there is the problem: Don't go throwing the kitchen-sink at a problem in an attempt to cloud the issue with irrelevant white-noise.
The OP specifically referred to the SFM SU-33's trim characteristics and I replied thereto. 'Overall' has nothing to do with the issue at hand. Trim has been buggy in the SFM planes for years and years and until it's rectified it's best not to rely on it for minute corrections, unless of course you resort to the hack you are referring to. Then again, that's not trim is it, justifying my advice as to not rely on trim in the first instance in that specific scenario ;)