The local Hiace is really bad indeed. Too bad it was never as well speced as the Subic Hiaces which feature 4WD, A/T, sunroofs and most importantly, the 3.0L EFI Turbo (may intercooler ba? I'm not sure) 1KZ-TE engine found in the Prado. Yes, the M/T Starex should be significantly more fuel efficient than the A/T. I remember a family friend's 2000 Starex Club A/T fueled up full tank before going to Baguio, and had to refuel again after arriving.

Pero in fairness it was loaded up with passengers and their cargo tied on the roof.

It almost didn't make it to the top.
The Starex CRDi SHOULD do better in terms of FC, especially in highway mileage as it is not lacking in power like our friend's poor Starex Club. 