VERY CLEAR !!! Thanks again.

I found a problem while doing the adjustment. I must be doing something wrong. When I set up the advance @3000RPMs 30° it's impossible later to get the spec value at TDC +/- 3° for idle.
I followed these steps when adjusting the timing:
Start engine
Disconnect both vacuum lines
Accelerate speed to 3000
Rotate distributor until advance reaches 30°
Back to idle
Reconnect both vacuum lines
But reading @ idle = 22°
Restart
Left both vacuum lines connected
Rotate distributor until reaching TDC = engine not happy
Stop
So I can’t get TDC at idle, not even close, after setting 30° at 3000.
I have vacuum in both lines. There’s vacuum at idle in the hose going behind the pod. There’s vacuum at the other hose going on front of the pod when at 3000.
I tested the pod and there’s no air leak. The arm moves freely when vacuum is applied and it holds it long term meaning no leaks.
What's interesting is that when I accelerate from idle to 3000RPMs and back, there's no noticeable changes in the advance figure. It barely fluctuates around 30° no matter the RPMs. Then when I reconnected the lines it goes down to 22° but never lower towards the aim of TDC +/- 3°
So I left it at 22° idle (30° 3000) where the engines seems stable and happy with no misfiring.
Anybody had the same problem?
Am I doing something wrong?