Yup... From other masks it is the first thing used in BPW calculation. I believe both injector flow and displacement has been found in $EE, so reversing should find one more number in the calculation.
The value 1461.5 below is the Stoich AFR, where PFI uses 365.375 which is 1/4 of the TBI setting, I'd guess this is to do with firing of injectors per cycle difference.
Code:TBI
; Val = 1461.5 * (VOL/RATE)
; VOL = Vol of 1 Cylinder in liters, (0.7125l)
; RATE = Injector flow in gms/sec
; 5.7l = 7.71 gms/sec (61.2#/HR)
; (VOL/RATE) = 0.0924 l/gm/sec
PFI
; Val = 365.375 * (VOL/RATE)
; VOL = Vol of 1 Cylinder in liters, (0.7125l)
; RATE = Injector flow in gms/sec
; 5.7l = 1.92751 gms/sec (#/HR)
; (VOL/RATE) = 0.3696 l/gm/sec