I don't like to do the payment from the software but a handful of my clients insist on it.  Several years ago, a new client at the time insisted on going that route.  For the first two or three years I would get a phone call from him because it didn't clear on 4/15.  Then another call because it didn't clear on 4/16 ------etc, etc.  It took awhile for him to get the hang of the idea there can be some delays.  But that's why I don't like going that route ------ their problem becomes my problem.