Very technical. Fortunate that I am a physics teacher and can decipher a lot of the short hand.
I think I get a glimpse of his thoughts, but I would like more.

HE HI= High explosive, high impact? At first I thought the technical acronyms hurt your piece- until my eye sort of auto-wandered to the keyword section and saw that you had provided a handy dandy explanation. Then I liked it a lot more. Unless you are trying to use the end for “punch” reasons, I would like to know what/who is being tracked/attacked before the attack begins. Just my opinion though. It does seem tailor-made for the challenge.

Robert,

I think it is a selector for HEAT (High Explosive Anti Tank, a shaped charge weapon) and an High explosive Incendiary round. But I could be wrong.

My bad. HE is high explosive and the HI LO switch is the rate of fire.