As a general rule you delay things if you make changes. Although Venlafaxine is on the list of SSRIs that they will generally waive if there are no other problems, by simply stopping taking it you have now changed the goalposts. Instead of having to show that you HAVE BEEN doing well enough on the medication that it is not a problem you must now demonstrate that you WILL BE ABLE to do well enough OFF the medication for it not to be a problem.

Since the FAA bases their assessment on a reasonable period of observation, by changing the conditions of the situation you have lost the ability to be judged on your historical record and must now twiddle your thumbs waiting out an observation period.