If they hadn't done a graduated parking fee structure the people staying at the Values, moreso All-Stars would lose out the most. Not only are the people staying there the farthest from the parks with the exception of AK they also have the least amenities AND they don't actually have any issues with parking spaces problems. For Values the % that the parking fee makes up would be a lot higher if it was a flat fee. If anything in % of the proportion to room rates Deluxe is getting a steal at $24 in comparison to room rates for Values.
As a random example:
Rack rate for All-Star Sports including taxes and fees for 9/7/18-9/16/18 will run $1,255.31. Garden Wing-Garden View at the Contemporary Resort for the same time period and rack rate will run $4,428.00 including taxes and fees.
If you take those numbers and apply $24 for the All-Star Sports that means it would be $216 and that equates to just over 17% of the overall room charge. Conversely for Contemporary Resort a $216 total charge equates to just under 5% of the overall room charge.
If you look at what they ended up with at $13 that would be $117 and would be just over a 9% overall room charge for All-Star Sports. Still high and unwanted but a lot better than 17%.
I don't think most people would figure out percentages but still.