Hi Amix, hi folks.
If you have not done it yet, disable Enable length snapping in Windows --> Model info --> Units.
Maybe you can also use larger units to avoid the problem that SU has with very small objects.
Use meters while pretending thay are millimeters. When done, scale down by 1000. Notice that SU will not accept 0.001 as a scale factor. It will however accept 0.01 and then 0.1 or the reverse. You can also use the pae measure tool to rescale the whole model or only a group or only a component.
Just ideas.