I logged the fuel consumption signal pulse width at different speeds and compared them:
The typical pulse widths are:
Idle = 450 uS
50 mph = 620 uS
60 mph = 740 uS
75 mph = 870 uS
Given that the idle pulse width is relatively large compared to the rest, I suspect that the settling time is contained in the signal. In fact, I'd bet that the fuel consumption signal is just a composite of all 6 injector signals with no other conditioning.
Also, since the Idle PW is less than 500 uS, the delay time should be something less. Maybe 400 uS. I have no idea. I'll have to play around with the settings against actual fuel burn to get an empirical value...in my 'spare' time.