Puah level should more dramatically effect fuel, especially with the new 'no refuelling' option.
Maybe its my league, which has some problems (detailed elsewhere) but with the new 'no refuelling' option, it feels like being able to affect fuel consumption with push levels could be more of a thing. If moving the push level affected fuel by .1 or .2 a lap, then you could have periods of trying to gap or catch another car and then a period of fuel saving ans have it really make a difference.