It is not deceptive.
Quick example for you:
On MB you make 2 offers for 1k, one wins one loses. You get .2% commission so $4 total.
On Parlaymakers you make 2 offers for 1K, one wins and one loses. Your total commission is 1.5 % for each so $30, but on the winning wager you paid $20 in GP commission so your net is $10....$6 more than MB.
Quick example for you:
On MB you make 2 offers for 1k, one wins one loses. You get .2% commission so $4 total.
On Parlaymakers you make 2 offers for 1K, one wins and one loses. Your total commission is 1.5 % for each so $30, but on the winning wager you paid $20 in GP commission so your net is $10....$6 more than MB.