Dealer's min might have been 10 cases, not 1 case. I'm spitballing as to what the reason might have been. He might have had a higher markup on VP and thought you'd just go for that, instead of walking out. My day job is sales, I'd have offered you as close as I could get to what you wanted, and preferably more than one option along those lines. Let the customer choose - as long as both choices involve buying from me. It might have been a pallet of Red Armor premix ordered from the factory, or me ordering a case of Red Armor Premix from Home Depot and marking it up from there, but I'd have offered you options.
I'd have been comfy running VP 40:1 as well, if it was cheaper. Price, and 40:1 instead of 50:1, was why I settled on TruFuel. Started mixing my own again after getting my 500i, but will likely go back to Trufuel. Even cutting up all I can for other folks, I just don't use enough fuel to be worth mixing my own. My saws are the only two strokes I own, all my other garden equipment is battery electric.
Lots of good options out there.