Well , All I can say is that I have done it this way for the last 2 years.. I keep NO credit card on file.. If they do not honor it ,I ask for a supervisor , tell them that I have this coupon and want to use it.. at that point , I am back to listening to Outlaw Country from PA to FLA . .
This has worked for me, results may vary
as far as the 5 months go .. I primarily drive that truck from mid April to mid September , with a few local weekend trips after that , so the 5 months works fine.. I just re activate the day before my first trip to Virginia in mid to late April...