Why can't I allocate the seats using the best seat button?

The seats are white with a red dot and all the other tabs (holds, allocations,best seats etc.) have their character or letter code as red also. This allocation is used by Group sales MOS so we gave them access to this allocation in  Modes of Salefrom the Ticketing Setup menu and then select the MOS/Allocation tab and in Hold/Allocation Codes from the Ticketing Setup menu and select the Allocation/MOS tab. 

Are we missing something?

please advise