Finished a bulk a few weeks ago and have some belly fat. To be honest, I never did any cardio and hardly any abs.

Right now i am cutting. Doing cardio before I eat breakfast. 40 min on an empty stomach on an elyptical staying around 70-75% HR. I then do 4 sets of 50 crunches on the swiss ball. I do this 6x a week. I also lift weights 4x a week (about 6 hours after cardio). I want to incorporate a few sets of ab workouts with a machine at the gym before I lift (4x a week).

What I want to know.... would this be considered overtraining the abs? I ask only because when I do the swiss ball crunches, I just dont feel that great a burn after I'm done.