Suburban SW6D Ignition Issue?

I recently went on an extended trip covering 3500 road miles with several 3-4 night stops along the way. at the first stop the water heater worked perfectly, at the second stop it worked perfectly until day three. As I was showering I heard what sounded like someone slamming one of the cargo compartment doors, I exited the shower to find the water heater fail light on I immediately reset it and it seemed to light normally. Next morning while shaving again heard the cargo door slam sound accompanied by the fail light. I simply turned it off and proceeded to my next stop. Being still under warranty I phoned the manufacturer of my unit and was told to check the burner tube for obstructions as well as the orifice. I removed the burner tube and orifice and could find no obstructions in either disheartened I reassembled everything turned on the switch and to my surprise it lit right up and worked perfectly for the next two days until I moved on to my next stop, there the beast reared its ugly head once more. this time I simply opened it up and wiggled every connection I could find turned the switch on and viola it worked for 4 days without fail. then again failed with the typical door slamming sound this time without moving the camper. I contacted an authorized service center and was told they would gladly work on it under warranty however manufacturers warranty does not include coverage for an emergency service call which would cost me $75 out of pocket unless I could bring it in and leave it at their shop and they could get to it in about a week. the tech I spoke with was very nice and told me he had run across this problem before and that it was more than likely the ignitor and told me to look for any cracks in the ceramic and that it was about a $20 part at any RV supply. So with my trusty screwdriver I removed the screw holding the ignitorin place and removed the ignitor upon very close examination i can see two cracks in the dull ceramic surrounding the ignitor rod but they do not extend into the shiny glazed ceramic. My question is could this still be my problem or am I chasing rabbits? I'll gladly spend $20 if it will correct the problem.