It's sever-side limitations. The IWT happens client-side. The server has to know you are intending to switch targets. So there is latency on one and not the other.

The easy fix is to set the targeting step to block for a second before going to IWT. Then have the IWT step block for a second or two before returning to the targeting step. Then at the parent node set the flag to reset to step 1 after a few seconds.

The way this will work is if you hit the target button 4 times in 2 seconds it will try to /target once and another attempt will be made to IWT.