Zandronum

Well i am trying to create a subzero´s ice ball, and i used timefrezee for make a similar effect, the only problem when the powerup duration is so close to end, the afected actor start moving but a very slow speed, i want to prevent this, i mean give the powerup freeze, but when i take the powerup prevent the slow speed for a instant normal speed.

Im not totally sure about what you mean, but I think you mean the "flicker" at the powerup end, right?
in that case I think there is nothing that will help you, unless you remove the powerup before the "flicker" occurs and thereby makes the effect I think you want.

lengthen duration of powerup by 10 seconds
TakeInventory the powerup at the time it should wear off

problem solved