Why my wallet (pool) is given an block reward of 12 ZDASH, and to others pools - 12,5 ZDASH?
you can look in block explorer
http://192.99.3.29, find your block and look what addresses received transactions for mined block. its in your pool setup, 4% goes to someone else, maybe some devfee
there is no dev fee in Zdash, please give me the TX for the block/blocks you mined and I will check.
each block should be 12.5 not 12.