Panning affects the Track Meter ... Right ?

I have an acoustic guitar recorded and when I'm panned to center, the track meter peaks at -15.1. If I pan hard left (or hard right), it peaks at -12.0

Does this sound normal to you all? 

When I mix, (i'm just learning), currently I first adjust my trim controls to get to -12, which should be very close to where I recorded. So, If pans do indeed change the output level, at least according to the meter, I suppose I ought to get my pans done first thing in the mix. Right ???

Thanks for any input,
Sam

Will do - thank you.