Unique Overworld Boss (a la DoomGaze)/Creating New Area Question

Code:

CA/52FC: E8    Set word $1FC2($07) [$1FD0] to $0078

CA/5338: A0    Set timer 0 to $0040 [0m: 01s: 04j], jump to subroutine $CA533F if it (expires?), flags: $8
CA/533E: FE    Return

CA/533F: EA    Decrement word $1FC2($07) [$1FD0] by $0001
CA/5343: A0    Set timer 0 to $0040 [0m: 01s: 04j], jump to subroutine $CA533F if it (expires?), flags: $8
CA/5349: FE    Return

It appears that the game uses a repeating 1s timer to continually decrement $1FD0 which is set to 120 just prior. It was probably done in such a way so that they increment/decrement it when feeding Cid fish.