Professional escrow is not cheap. The first year, when you have to demonstrate a complete build and 'bring up' process with them the price seems pretty good as it's a lot of work. Funnily they don't seem to offer a multi year deal.
The second year there is much less work but they double the cost. You go along with that as it takes a lot of work on your part to engage a new escrow firm from scratch.
The next year they double it again. It's still demanded by your large corporate customers and you try to pass on the costs but they don't want to pay it.