You’ve pinpointed the error.
→ But I only set 0.1mm kerf
(0mm Kerf) 100mmx100mm = 400mm away → Length of time 9 seconds
(0.1mm Kerf) 100.2mmx100.2mm=400.8mmaway → Length of time 6 seconds
The kerf offset should not be rounded.
And even if it is, 3 seconds at 0.1mm kerf is incomprehensible.