I find this problem much less pronounced on CTS than on CT. On CTS, as others have already stated, there is almost always one, and only one, correct response. If you played something else you probably missed the motif completely.
On CT this is not the case. They have lots of problems with lots of great move opportunities, but only one 'most correct' move. All other moves are incorrect, no matter what advantage you would have in playing that line.
The most frustrating of these is forced mate situations. On CT if you see a mate in 6, but there was also a mate in 5, then your answer is incorrect. It doesn't matter if both lines are forced or not. This is very frustrating because I stop looking for better moves once I see a forced mate. I suspect most others do as well.