As long as they get along ok, and aren't bothering the hens too much. If you see hens start to miss feathers or the low totem pole roo getting picked on I'd rehome one. If alls going well right now though no reason to mess it up.
I've run at that ratio and everyone's been fine. I think the key to it for me was free ranging, or at least making sure everyone had LOTS of space. This is a "your milage may vary" issue, you just need to keep an eye on the hens and make sure they don't get overmated. Bare backs, lots of screaming, violent matings or roos ganging up on a hen are things to watch for. You'd need to pull roos out if you see any of this.