For now we allocate ZBT based on whether its a 20 min game or not for DOTA2. Also most games on famous modes (turbo) have average end time of 20 mins. But many times they are like 19:30 or 19 mins. Half the game are above 20 and half below. Also if one losses at 20:30 he gets 46 ZBT and if one wins at 19:30, he gets 20 ZBT. This method is unfair to those who play to win and win fast.
A better way is explained below:
1. A win in any case should be awarded more than a loss, irrespective of time taken to win the game.
2. If it is necessary to have time slabs then have some close relevant time slabs such as. below.
0-10 min 20 ZBT, 10-15 min 40 ZBT, 15-20 mins 60 ZBT and 20 min and more 80 ZBT for win. And half of it in each case for a loss. This is justifiable and logical.
Hope you incorporate these suggestions.
Regards