Doesn't it boil down to the fact that it doesn't matter how they come, as long as the come?
I am quite sure that many altar rail conversions are pure emotion with no real commitment. Likewise, I would think that many appointments in the Pastor's office would lead to a "commitment" if for no other reason than to end the appointment.
I would suspect an "office" conversion to be more likely real than one at the altar rail..at least there is time for one on one prayer and some teaching .
But either way God is God of that moment