Quest Booster pack Ratio

Hello, in quest mode I've modified the pack ratios as follow :
7 common
5 Uncommon
3 Rares
so why do I still get the "normal" (10 common, 3 uncommon, 1 rare, 1 land) booster format when I win ??
7 common
5 Uncommon
3 Rares
so why do I still get the "normal" (10 common, 3 uncommon, 1 rare, 1 land) booster format when I win ??