Ah, that's the beauty of 'parallel process' common events.
Let's assume that you're using regular events to add '1' to a variable called
0001: Game progress
Now, have a common ev. parallel process that checks the 'game's progress'
Comment: If, your game's progress reaches a certain point...
<> if [0001: Game progress] >= 20
Comment: Then turn your ABS switch on...
<> Switch: [0001: ABS Switch] = On
<> End if
Now, have another parallel process that only works when '0001:ABS Switch' is ON.
<> Var: [0002: TimeCounter] = 0
<> Do
<> If [0002: TimeCounter] >= 20
<> Break Loop
<> End
<> Wait 1.0 seconds
<> Var: [0002: TimeCounter] += 1
<> Loop
<> Sw: [0002: ABS Turned On] = ON
Basically, you'd be using 1 variable to control your game's progress...
And one switch to tell the system that the game's progress has reached
the point when the ABS will start to be used...
And another variable to count the seconds that pass before the ABS
will actually take place (your delay)...
And finally, a last switch that turns the Action Battle System ... ON!
It's been a while, so I'm fairly certain that my commands aren't all correctly written... just closely approximated.