Make overtime a variable credit limit. By that I mean make it so that players don't know how much they're getting. Example:
players won't know if they're getting -

-Pistol+low eco smg overtime round 900-1800 credits.
-Smg/Low eco sub rifle round 1800-2100/2200
-low eco standard rifle round 3350
-standard rifle round usual 4300

that way overtime is as random as the floor your picking although the winning team
chose side.