Make a square of 10 x 10 or something.
Engrave it or cut it, then
You can goto machine settings…
Then click on calibrate axis.
enter the value it is supposed to be and the value it is after burning for x and y axis.
This might also help.
After digging around, I finally found a page on the SainSmart site linking to the LightBurn configuration settings for my Jinsoku LE-1620. It appears my $101=80 was incorrect, and it needed to be set to $101=160. After making the change, everything start to engrave as expected.