If you put 10w back in those puppies, it will be much stiffer with your current settings. Back the compression and the rebound off a few clicks and ride it again. It should make a difference.
Did you do one fork or both forks?
How did you measure your oil (480ML)? Did you compress the fork cartridge until all the oil was out of it? If not, then you most likely have to much oil plus you have 10w which is twice as thick as the original 5w.
Sounds like you may need to disassemble them and start over?
By the way, to much oil means less air space and that will create a higher pressure as the stoke compresses creating more resistance.