@Leslie181, the phrase "no charge for additional guests" appears when you do not have any per-guest charges at any number of guests. By adding the $300 / guests over 10, you should have made that "no charge for additional guests" disappear.
And by keeping your max at 10, it should now be clearer to people to NOT bring more than 10 guests.
My listing has a max of 4. The phrase "no charge for additional guests" appeared, which made it seem like more guests would be OK. Hosts on this board said all I had to do was add SOME sort of per-guest charge, even if it was never applied. So I put "$50/guest after 4", but since the max if 4, it is never applied.
But the phrase "no charge for additional guests" disappeared.