Impatience set

Impatience set doesn't seem to work for me. Doesn't give me any extra speed. One time it even gave me negative speed, but I haven't been able to duplicate that bug. Anyhow, is it something I am missing or is the impatience set just not working any longer. When I try to use the impatience set i equip a tower with 3 items of the same type. The speed is not affected at all from skipping to next wave.

Sets only work with different items

@kami, Mind Blown. THANK YOU!