[State 5210, 3] ;invincible
type = NotHitBy
trigger1 = Time = 0
value = SCA
time = 15
This one means that you are invincible for 15 ticks right after the recovery starts [trigger1=Time=0].
[State 5210, 4] ;can attack
type = CtrlSet
trigger1 = Time = 20
value = 1
This one means that you can attack back, even while in the air, but only 20 ticks after the recovery starts.
[State 5201, 4] ;invincible
type = NotHitBy
trigger1 = 1
value = SCA
time = 1
Here, the "time" parameter doesn't have impact because of [trigger1 = 1] , so you're invincible throughout the whole state (until you land).