Either last month or the month before, a bill was passed by congress exempting rv motorhomes from the 20,000lb axle limits. We are now now permitted to run 24,000lbs the same as passenger buses. There was a posting on the IRV2 forum about this. I would imagine that an internet search would also show now if one was inclined to look for it. It was part of an obscure Transportation Dept legislation.
The above applies only if your axles are actually rated for the additional weight. As I understand it some manufacturers only rate the axles according to the tires they installed on the coach at the time and the axles may have additional capacity up to the 24,000lb limit. You must either crawl under the unit and check the manufacturer's tag on the axle or call the coach manufacturer and get the correct maximum axle ratings from them.
Good luck and safe travels!