Torch height vs cut speed chart

hey guys, I’m cutting brackets on 1/8 steel today and the sheet is bowed up a little, enough that on my last stretch it didn’t cut though completely. This made me think a little more about torch height vs speed but also this: my Hypertherm cut chart stipulates “drag cutting” for that chart. I’m going on the assumption that dragging the torch will allow you to cut thicker material, so since we aren’t dragging on the table and are set 060 off, is there a rule of thumb to reduce the speed a certain percentage?