Q: Cannot adjust temperature despite changing setings on the control knob. Is this Standard?

I been asking help on this issue, since I need a caucus from reliable mechanics, who had the experience on this situation. The cabin temperature due to this condition continues to drop (about 18 degrees Celcius even less). For this reason, we always keep an extra coat in the vehicle. And the drop of temp maybe compensated, or not noticed if you are driving in a hot and warm day. If the outside ambient becomes cold, or reaches near condensing humidity, the cabin temp, which had drop, causes too much condensation and fogging, thus you operate your wipers for you to clear your view. Later we control the temp by switching off the AC button. Later I realized that my compressor is short cycling. The question now goes, is this standard operation? Worst to know in the end that the AC is being controlled by PCM.