I'd do alot of reading also before signing also. There may be a clause in there about depreciation so that if that $4000 Dometic 4 door fridge goes after 3 or 4 years they might say, oh well, lifespan expected may be 5 years, we are only paying 20% on replacement.
I did have that Dometic $4000 fridge go after 5 years use & many thousands of miles of bouncing back & forth across the country. The attitude on my part was, Oh well, guess I got my moneys worth, & swallowed it.
Same with the truck. Preventative maintenance has so far saved me from any huge failures.