I do agree a say, three day pass for $10.00 would be a good revenue maker for Michigan.
I know many people that stayed in northern Wisconsin last year. To avoid the permit cost. For me, two sleds. $90.00 really seems like a lot to pay. I think also a second sled should be half price at least. Like Wisconsin state park passes for autos. Would make more sense.
Ya, if you can spend $8-10k on a sled, $45.00 shouldn't break ya, but it's the point of it.
Already big cost if paying for hotel and food, drink, etc.
Two years ago, went to Munising in late December. Had hotel, food, travel, two trail passes, and a simple mistake cost me another $125.00 for trespassing. Became a $600.00 weekend pretty quick. Then on top of that, my jobs kept me local the rest of the year. Didn't even get to go back. Three day pass would have been nice.
But to answer your question, sorry, I don't know the answer about sales up or down.