I have been using LB for about 2 months, it has been working great. I upgraded and purchased a subscription. For some reason I can be working on a project and my burn speeds will change from 30 - 40 % to 1570 aor another high speed setting. When operating it moves so slowly that it burns a hole in the project. Other time it works normally with a speed under 30-40% and a power of 80s. I have a Xtool Pro 20W and running LB 1.3.01.
It may be of value to note that along with what Jack offered - the units of speed, in mm/min or mm/sec the Percent of range % applies only to Spindle Speed or Laser Power in GRBL. There are a lot of different units of measurement and it can be disorienting.
When opening files with File - Open, the settings connected with the file should be preserved. If you Import the file, (or drag and drop) the current settings are preserved.