Time decay for flag_short

[Ongjming]

Was wondering if there could be a time decay for flag_short? (Something like how battery/fuel kept burning/refueling over time)
Could certain flag_short value be tied into general zombie spawn rate with the default/server set as the baseline to alter from?
(e.g. scenario: zombie increase in spawn rate over time as the flag_short value gets smaller towards 0. Players taking on zombie killing quest could increase its value, eventually making "clearing out an area" probable and a repeatable task.)