I´ve been checking out the DW Captain in the Rites of Battle book, and even though they request that you have Command +20, they later offer you command, command +10 and command +20 as part of the alternate advance for Captain. I´ve been searching the forums, and the only thing I could find was that it´s simply just an errata. Has there been any word on what those might be changed to (or if they simply have to be removed)?

There's no need to remove them. Just ignore them. The Captain gets plenty of other things, and it's not intended that they be replaced.

In the core rulebook there is mention that replication in tables should be ignored. It is simply there for the sake of possible future compatibility.