It would probably make sense for you to call the company and ask what the rate would be for your combination of work. This is particularly true as you do both land and water.
If you are an RYT you could also ask for a quote from the company through which they offer insurance, making sure it covers the pilates as well as the yoga, just to see what is the best coverage for the price.
I actually think IDEA worked out an excellent deal for its members and that the insurance they offer is a very good value. I teach group ex as well as yoga and am covered for that.