I have a plow on off and on all year and drive 50/100 miles at a time. I see thirty and forty degree differences traveling with my blades angled to one side and if I have it straight and raised a high a possible. Lowering the blade when it is straight is only good for about half that.
Have you talked to the dealership about your issues?
They certainly should welcome knowing of your issues with mounting so they can deal with the problem and could get you a little extra service in the future.
It is unfortunate that you had the overheating problems but it is not really the installing dealer's place to examine your vehicle's mechanical condition. I agree there is benefit for the dealer to discuss/advise you on load capacity enhancements, cooling add-ons, electrical supply improvements, warning lights and deflectors, they add to the bill
Not all service shops see instruction as a part of their product, in fact the lower the price the less service is factored in, after a certain level the base plow cost everybody the same amount, the less money you pay the less service they can afford to supply.