On: Is it unethical for me to not tell my employer I'v...

[taneq]

I'd guess no matter the original context, once you're being 8x more effective than your colleagues, it's due to some kind of engineering. So in agriculture, your 8x hay mower is the one who's built himself a scythe instead of using a hand knife.

[frostymarvelous → taneq]

In that case, should he tell his employer he mechanized his work?