I have that zip tie tool also.. I wish I would use it more often.. those SHARP cuts sure will cut you up.. my hands right now have about 15 small cuts from those zip tie ends(from doing the MSD box)... 99% of the ties I use are the black UV ones.. I have bags of zip ties of assorted sizes
Buy the cheapo white ones for initially assembling the harness. Better quality black ones for final assembly. Adds up when your using hundreds of them.
If the results don't match the theory, change the theory.