Weird Kerf Offset behavior

Have an odd one - ok - that has me scratching my head… Ortur LaserMaster 2 “15W” (like 3.5W output), latest Lightburn software on a Mac.
Cutting some EVA foam thats around 3mm thick to do inlays. I’ve cut my inlay, with a +0.3 outwards kerf offset. 500 mm/min / 80% power and 3 passes on some grey foam.
Cut the “background” foam (black) with -0.3mm inwards kerf offset, 500 mm/min / 80% power, 2 passes.
The design is a word with block letters and some lines (thin rectangles) - all in about 8" long and 2" wide. Cut the inlay letters… ok, cut the background - the inlay is way loose. I used one letter and run a kerf size test - cutting the same letter from -0.3 to +0.3 to check the right size kerf for the background.
Here’s the weird part - when I cut the ONE letter for the background, the inlay (grey) fits in the black background cut at -0.3 kerf perfect… so maybe I didn’t have the settings as I thought - go back and cut the whole background with the settings of the one letter - and the inlay is way loose again…
What is going on?
I don’t understand why cutting 9 letters across the full design size and the lines is resulting in larger cuts (which are consistently larger for each letter - than when I cut one…
For further head scratching - I did the same last night, but with a little thinner foam, and was able to get a perfect fit… in that case the inlay was being cut the same, perhaps with a little less power but 3 passes, and the background was cutting in 1 pass vs. 2.

UPDATE - figured it out -Solved the mystery… I had a box around all the text to cut the background out clean - and the text shapes and the outline were all in the same layer. I guess as a result Lightburn was calculating the offers differently for the text - treating it as an inner vs outer shape. Moving the box to its own layer, with all the same settings - cuts the background now as it should…


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