I have handled every kind of Extended warranty,Factory,Insurance claim there about ever has been.I have had months that it made up about $50,000 in parts and labor sales.The AFTERMARKET EXTENDED warranties(service contracts)are THE worst for denying claims.I have had claims denied for sludge,burnt fluids,original filters,(never changed)abuse etc.But NEVER asked the BRAND or WEIGHT of a fliud in a differential,transmission or engine.Seen many total brake failures due to OIL in brake master cylinders and such(Thank you Quick lubes!BIG easy $TICKETS!).The guidelines are kinda broad also.Maintenance has to be the MINIMUM as PER the owners manual to be compliant.Unless somethings changed over the last few years thats how it was for the previous 25 for me anyway.I had one summer that we had SO many vehicles come in with failures and covered by a AFTERMARKET service contract company that THEY assigned a FULL time independent adjuster to our shop! He(former BMW engineer from Holland) was involved in EVERY vehicle for a month or more with that policy attached.(I bugged the ONLY phone he was allowed to use in MY office.Making SURE he shot straight with THAT company)Then again the WEIGHT or BRAND of fluids was NEVER questioned.Shop was in a BIG MALL and that summer was slammed with work.Employees HAD to park across the road as we had so much work(30 techs)and ran out of room for BROKE cars.Oh and the BRAND of vehicles was NOT domistic!