I had to cut some 10mm acryllic plates to construct a box of it. My P2S is almost not able to cut through it at once. perhaps only at full power at 1mm/sec, but I always do 2 runs to get fully through it. 

I discovered that the z cut angle, so where the beam should cut exactly straight downwards  and in a 90 degree angle with the slates or honeycomp panel is angled. See attached image. This results that I cannot make a nice fitting box with these not straight angles.

I doubt if the bed is not fully levelled, or the laser head has some miss alignment.

When cutting 2 or 3mm material you won't notice, but with 10mm material you will.

Does anyone experience the same behavior? should it be a perfect straight angle, or isn't that possible due to the focus point of the laser?

Xtool suggested to recalibrate the X axis, but I doubt of trying that, because that probably won't solve anything in the z axis.