I noticed the same issue in an attempt at trying to use fan only, with the GoM reducing the estimated range by 10% regardless of having the AC on or off. While I haven't paid too much attention after the first few days of driving my RAV4 and don't know if it improves its estimate with usage, I assume the operative word is guess in GoM, at least when it comes to the climate control usage.
With that being said, an electrically driven variable speed compressor is pretty efficient, and I wouldn't worry to much about using the AC even in the benign environment we have here in SoCal. While I would guess the compressor could pull a kW or two peak power, the average power draw is going to be quite a bit smaller with a more typical heat load on the cabin. Driving style is going to have a much more significant effect on range, so if you are really trying to eek out those extra few miles, just slow down. In my case, I've been either cracking the windows at low speed, using the vent, or turning on the AC if the previous two don't keep me sufficiently cool and not really worrying about it.
