Why you don't do a 5 second count in your head

[Fritz]

My closely guarded 5 sec mechanic actually is 4 arm swings on the premise that there are a lot of 1 sec CG instances, so that first sec is in my head and then I start the arm on 2.

For those that say they do an arm on the first second, don't you find your arms in motion a lot then? I originally tried it that way and had a senior partner tell me to stop it and just count 1 in my head and then signal. Before that, my arms were getting tired from constantly being in motion.