You'd have to ask performance tuners whether they can do it or not, there's no mechanism that's available other than pulling out the VAG-com every time you wanted to turn on the AC, which isn't practical.
To answer your question, NO, but in a long way, yes. If your Q.A. is too low you could see a bit harsher idle roughness when the AC is on vs off.
If you can feel or measure a power loss more than 1-5HP on a dyno on an engine with about 100HP stock, you have a SERIOUSLY F'ed up thing going on and any feeling you have of MORE POWER is clearly a placebo effect. Now thats not to say that at idle or about 1.5HP output that yes the engine should see a noticeable difference and the ECU should be correcting the GPH input and Q.A. of the IP's IQ.
If i remember right, the procedure calls for the AC to be off when doing your hammer mod or adjusting your Q.A. but its been a while so i dont remember more am i looking it up.
If your car is noticeably slower with the A/C on I think there's something wrong beyond the IQ. Injector issues, weak pump, air leaks in the fuel lines, poor boost or a boost leak...could be any number of things. But I've had two MK3s and now have a B4, and it drives the same, A/C on or off. Your car should, too.
There is also a relay under the center console that turns off the AC compressor’s clutch once you have a significant enough engine load. Not everyone likes that behavior and some bypass it. These details aside, IBW is correct though with the caveat that during partial load , you’ll notice *some* reduction of power, but nothing dramatic.