I had one of these tables before I expanded my sewing room. Really nice how it all folds up and away if needed. I gifted mine to a friend who moved to a small apartment.
However, as the cabinet is actually a fibre or particle board covered with some sort of melamine like finish, I am not sure if the "wood" would hold the weight of a shelf supporting the machine? Perhaps someone with more knowledge of woodworking and engineering could answer?
It would be a shame to see you modify the cabinet and then have it not support the weight or vibration.
edited to correct spelling error!