You take your Max Capacity 22500, x by .78 which equals 17550, then minus your taxi fuel off which is 200, which should leave 17350.

 

You also need to check MTOM......DOM + TL + maximum fuel must be less than MTOM

So, maximum allowable fuel must not exceed:
MTOM - DOM - TL
66200 - 33500 - 10600 = 22900kg

This is more than the tank capacity less taxy(as beech has calculated)....so max fuel is within limits.