HVAC temp control?

[hedgehog]

This is my first winter with the GTO and the temp control seems to require a lot of back forth to get the temp comfortable inside the car. Once I get it reasonably warm in the car I usually turn the temp control down to somewhere in the middle range, but in the GTO its blowing way to cold there. If I go maybe 3 or 4 notches past center it warms a little and then almost suddenly feels like it goes full hot. Backing the knob up 2 or 3 would seem like a good adjustment at this point but has no effect, it stays very hot. So I back it off until I get a result, maybe 2 or 3 more and I get the expected result of very cold.

Is there something going on here that I need to look into or is this normal on the GTO?