DUI at Marathahalli bridge

Was travelling on ORR from Bellandur to KR Puram after a Christmas party. 2 cars, one was driven by a guy who had 1 beer and the other who had 2 pegs of whiskey. Both were caught for DUI, the guy who was under the limit was asked to pay 2k; asked not to drive from that point. The guy who was over limit was asked to pay 4k and asked to clear the scene immediately. I know both were bribes, but what is the law? Why was the guy under the limit had to pay 2k, why was the other guy (even if he to pay double) let off faster?