By picking to use the Computer MAC it now sees only one. As long as it works no problem. If you find you can't reach sites again try going back to using the Default MAC.
Anything on the WAN side of the router only see the router MAC so I'm not buying that the one MAC is better than multiples (especially since you can't set everything on your LAN to the same MAC address).
I reason that the MAC clone idea came from back when there were few home routers and your Internet IP access (whether fixed or dynamic) was associated with one computer that you had to register with your ISP. I expect that cloning is no longer necessary as modems are now very addressable and the task of making sure someone isn't stealing your service has been moved to the modem.