In race Fuel %

I know the fuel usage from your TD is measured at Hold position but my question is this. . .

How much difference in percentage of fuel used is each live aggression change (IE Push, Push Hard)? 1.5% more per lap for each stage?

Assuming your Technical Director is correct [which from experience he wont be] I'd say approx 0.1l per lap [per change] although depends on the length of the track, and your fuel/engine suppliers, possibly even driver skills

to be fair brady mate it dont change much between push hard and push most time it tends to not jump it  moves more when on hold postion and then back off.

^ suppose yeh, maybe .1l from far left to middle, then another 01.l from middle to full right [although the difference in tyres temp etc will change loads]