What is the de-ice bill?
Is it billed as 250Lts of XXX TypeII or total used @ mix rate?
It would be billed as written in the SGHA. Normally reference to either a rig call out fee and a couple of rates for 100% de-icing fluid, 75/25 mix. Alternatively, no rig call out and a specified retainer and a higher rate for the fluid at different mixes.
Not certain, but I don't think 50/50 is used, but I am not a de-icer either so happy to be corrected . . .
GA