They aren't paying above market they are simply being billed for the actual terms and features they are demanding.
And usually those fees are close to negliable, should be considered in pricing as part of the overhead and are simply cost of doing business.
Good news, if you are already at the point your customer provided paper worl to be reviewed, you are pretty advanced in the sales process with a decent chance of making the sale.
There are laws (in some places) that prevent you from charging the government more for a product than you charge another customer. So you'd really want another SKU for a higher price tier to make it definitively a separate product rather then just telling them they'll need to pay more if they ask for something.