Mixer fader and input level

[Greg555]

I read the book "Offical Pro Tools Courseware".
In there it states that the mixer faders in Pro Tools has no effect on input levels.
But.... when I plug my guitar into the Mbox 2 mini and check the levels the input level decreases when I lower the fader knob in the track. In other words I play the guitar and the level goes up. when I lower the fader knob the input level goes down. So... is there something Im missing here?

My stuff is below. I just uped to PT 8.0

Alienware area 51 Mobile Desktop
portable setup

win xp home
Pro Tools 8.0
V One Toontrack sample player
Xpand plugin
Mbox 2 mini
Korg pandora effects unit
CPU Pent 4 2.9 gz
3 gigs ram
2 hard drives both 7200 rpm
Pro tools sessions stored on HD without the Win OS
Traveler guitar electric 6 string
Mogami audio cables balanced
Nothing running that doesnt need to be running
A pair of sony $20 headphones