The laser cuts the parts to a different size than the one set in the program

the laser does not cut to the size set in the lightburn
in the lightburn i select 15 mm size of a pice that i want to cut but the laser cut my pice at 18 mm. what is the problem? and the letters but the numbers cut them in the mirror, I mean I can only use them on the back

Hi, you can adjust the cut size by changing these two
$100=80.000

$101=80.000
160 My machine cuts properly

whit this parameters work perfect. tks