Onegaishimasu. Sometimes if you put your elbow in uke's back while doing shihonage, the elbow works as a sort of brace to stop the turning.
If I understand you correctly, then I agree. If you pull the elbow away from the body you can cause a world of pain...and you have to be careful, but it gives some beautiful control over uke where you can play with them and set them down right in front of you.
In the end, all the moves are hit and miss...from time to time what seems to work doesnt...just cyclical I guess.
I had a time of day with shomenuchi sankyo today for only god knows what reason. It happens I suppose.