One word: Resolution. The higher the metering capability of a MAF, the less resolution the meter has.
Resolution - basically, it has to do with airflow vs. MAF voltage. Two factors affect it: Physical size of the MAF, and injector size it's calibrated for. For example:
(all numbers are hypothetical and just to describe resolution)
Meter "A" - Can flow up to 800 cfm.
Meter "B" - Can flow up to 1000 cfm.
Typical MAF airflow during normal driving will range from 50-200 cfm. This is the same no matter what MAF you are using.
Now, Meter "A" flows 800 cfm at 5v. Meter "B" flows 1000 cfm at 5v. 200 cfm difference, big whoop, right? Wrong.
Now, at 1.25v, Meter A flows 200 cfm. At the same 1.25v, Meter B flows 250 cfm. Do you see the trend here? When you start getting into lower voltages/airflow levels, the bigger MAF has a harder time covering the bigger spread of airflow with the set amount of voltage available.
Kinda like fooling with the "mouse" speed on your computer. Set it up to as fast as it goes, and you can easily move from side to side on the screen with a flick of the wrist. Try to select a single letter in a text document at the high speed, though, and it's a whole new ball game. The amount of distance the pointer covers vs the amount the mouse actually moves makes it very difficult to define exactly where you want to be when it is a very small area. Set the mouse speed to slow, and you can easily select what you want.
