$59 per month is low. Just make sure the billing portion is good.
Can you get your software updated so you can continue?
We use Lytec and I believe it will be about $300 a month for the cloud version. We use the server version. This works for us because we can have unlimited clients, and unlimited seats on the server version. We have to update, but it still works out.
We charge a flat fee for most clients. We are in NY and percentage billing is illegal. The issue with hourly fees are that usually you don't take into consideration the other expenses. Clearinghouse fees, software, computer upkeep, printer costs, email (if you have to pay for secure), phone & fax lines, office materials (pens, paper, stickies, highlighters, etc) and that doesn't even cover electricity, heat, space and taxes. The per hour fee then sounds way to high for the provider because they are thinking they could hire an employee for that. But they don't take all these other things into consideration. With a flat fee model you can allow for those.