Strange interconnection

My 92 OCC's AC was not making cold air after being rebuilt. I found that I did not put enough refrigerant in it, so I took it to an AC shop. That worked well and now it works properly. The strange interconnection is that the idle was about 1K with the AC turned on or off before repairing the AC, and once I got the correct amount of refrigerant in the car, the idle returned to normal. Does anyone know if there is any relationship between the AC and idle? It now idles the same at about 650 with the AC on or off. I have never seen anything else like this.

That does seem a bit odd. Maybe they fixed a loose or disconnected vacuum line?
I know the computer will kick up the idle slightly when the ac is turned on to account for the extra drag on the engine.

No vacuum like issues before or after that I know of.

What are the inputs to the Holley MPFI system? Does it have any awareness of A/C operation?

It is the stock TBI system on my white 92, not my 91 with the 454.