Help a noob with his Z height issue

[Roberts_Clif]

Knew it was a long shot.

Post your 3D Printer specs, along with which firmware you are using.
You may need to calibrate your steps per mm on your Z-Axis

[Verkeer]

Knew it was a long shot.

Post your 3D Printer specs, along with which firmware you are using.
You may need to calibrate your steps per mm on your Z-Axis

Eh it was worth a try, thank you.
Which specs are you referring to?

I've got two Prusa i3's.
Below you can see I tried printing two tubes, 100mm in height. The white one printed 100%, the green came out to 74mm.
Not sure about the other printer that got it right, but the questionable prints are coming from the machine that has
Marlin 1.1.9

Steps currently on Z axis is set to 8000 steps/mm
So my initial question was why 150mm comes out to 127mm, and fixing steps should then be on 9448
Now the new print was at 100mm and came out to 74mm, so then changing Z should be on 10810...
Thinking something else is wrong.

20200721_192820.jpg