I must have worded it poorly because you are confusing two different points that I made. The first point was:

Most attorneys find it is more effective to present evidence during a trial than after their client has been convicted.

Hopefully you don't find fault with that statement.

The second point I was making was in response to rayiner stating that arguments can be waived on appeal if not made in a post-trial motion. That is not directly applicable here because the argument in the post-trial motion is based on supposedly new evidence which is not applicable to an appeal.

Regardless, their client would have had a better chance if they made the argument in trial than in a post-trial motion.