Gain control unreliable

I have several takes of a guitar part. The first was artistically good but I'd recorded it way too soft, so I boosted the gain by 10dB to match the others.
 
Unfortunately it appears Sonar X1d ex ignores the gain setting when exporting tracks. 
 
gcolbert suggested normalizing the track. Good idea (thanks again!)
 
So I zeroed the gain (doubleclick) and normalized to 6dB to get the same waveform height as the other takes.
 
But now the audible and meter level of the soft track was way too high! It was hitting the end of the meter all the time. The other tracks stayed under 6dB and NEVER hit the end of the meter range. And yet the waveform heights were all the same now!
 
I double-checked: Gains all the same (zero). Faders all the same. Pan all in the middle. Not in key "O" mode (why is it listed as Unassigned in the Keyboard Shortcuts? Also weird). No EQ (PC off). No effects. And yet that track was way too loud. I couldn't understand it.
 
After much frustration I had to call my client to say I cannot deliver yet.
 
This morning after a worried night, I started Sonar and fiddled some more. By pure chance, I tweaked the gain control a little, and WHOOPS! Suddenly, the meter and audible level dropped to the same as the other tracks!!!
 
So clearly there is still something not quite right with the Sonar X1d PC/Inspector strip. Double-click sets the Gain knob to zero, but the gain may not always change.
 
Man-oh-man. In future I'm not going to use the Gain knob.
 
There's a bunch of little non-reproducible things the bakers should have a look at.