Mugwumps.
Presumably if you think Gama were wrong in changing the charge-out rate, then you've seen this by a loss of customers? It always seems to me when I've flown into Fairoaks that Gama have loads of aircraft in work so they don't seem to be doing too badly.
Manns had a reputation for very high bills and I can't imagine that former Mann customers would have stayed or returned to Gama unless the excessive charges had been brought under control. Ultimately a company has to charge a sensible amount to cover it's costs and as long as it gives good service and value for money then as Cockney Steve says, the headline rate really doesn't matter.