Luban scales Laserfile

Hello, I have the following problem.
I have created a box ( - 90 mm x 280 mm x 55 mm (with bottom). When I transfer the file to Luban the size is scaled (about 75 mm x 230 mm).
A smaller box (130 x 110 x 55) works fine.
I have the Snapmaker 350 and the 10W laser module. Firmware and drivers are up to date.
Does anyone have any ideas?

This sounds like a well-known Luban import bug, alas. Rescale it inside Luban, or shell out for the alternative laser program Lightburn, which is more capable and better-behaved.

Thank you for your answer.
How can I scale within Luban (mm exactly)?