Laser does not burn through birch

I use 1,2mm birch plywood, Laser module (1,6W) set to correct focus (with the little boxes), to 100% and speed 70mm/min. I do 2 runs and I can feel that there is a gap in the wood, but there’s no cut-through, I would say around 80% of needed depth. Second run was with Z -0,5mm to reflect the deeper cut from the first run.

I got a totally different result with plywood of unknown wood (perhaps poplar) but double the thickness (2,5mm). Two runs and the sample is almost like cut-out.