As I mentioned in my comment, if you are not looking for a workaround then it sounds like to me you're suggesting a feature change of Google Maps. But after you replied I can see you just want to confirm if this is the case with Google Maps API service.
Well as you can see on the GMaps bug tracker, there is already an ongoing discussion to have the restriction raised or removed. The free version limits you to 10 waypoints per request and the paid version (your version) give you the full access to 24 waypoints. After looking around, it still appears the 'paying them money to remove restriction' approach is not going to work with Google as shown on their documentation and in this Stack Overflow post. That waypoint limitation is put in place to prevent downloading whole GMaps database via repetitive routing.
The only approach is to use a work around or another service. I suggest if you have 40 waypoints for example, that you stitch together two routes using the same color and make them appear to be one route.
I know it's not the answer you want, but it's likely that Google can't handle the large requests that you're imposing so they are purposely bottle necking their waypoint limit to give everyone a fair service. You can of course contact their sale department and see if they will offer you a specific limit, but that will come with a big invoice as well :)
Good luck on finding your solution and let me know how it goes, very interested to see if Google changes this limit or give an official work around.