Good Sam Extended Service Policy on original parts.

I own a 2002 Country Coach Intrigue with a Cummins 370 ISL engine. It came with a composite (fiberglass) oil pan. The truck pan would not fit due to the low mounting of the engine in the Dynamax frame. The pan started to leak (2013) where the return oil return line fitting was fashioned into it. Per Cummins the composite pan is no longer sold (obsolete)and is replaced with a steel oil pan. The original pan cost $545.63. The steel pan conversion kit cost $1726.17 through Country Coach. After filing all the parts and labor invoices with Good Sam Extended Service Plan, I received a check for $1747.64. The reimbursed me only the original price of the composite pan siting that their policy is to pay for only original equipment replacement not upgraded parts. I sent them a fax copy from Cummins stating that the composite pan is no longer available and that the steel pan is now the standard. (not an upgrade). GSEW's answer to this was the policy pays for only original parts, even if they are obsolete. My total repair bill was $4863.52. I was reimbursed only $1747.64. Great policy! Seems to me that GSEW needs to update (not upgrade) their part replacement policy. I imagine there are a lot of older RV owners who think they are completely covered. By the way I am a life time member of GS and have most of the available coverages. Hope I don't need to use them.