HSD 130 dross on 1/4"

[rikduk]

I have a Hypertherm HSD 130, it cuts BEAUTIFULLY.
Except when i cut 1/4 steel.
50 amps, oxy/air, all book specs, 65 ipm, 108 volts.cut height 0.100"
I always have dross. Not much, maybe 1/16 big, but regurlar and all along the cut.
I have no dross when cutting everything else.
I tried from 58ipm to 80ipm, with voltage varying cut height from 0.06 to 0.110" (not on the same piece)
Is there an updated cut chart?

Thanks

Richard