Wavelab Pro output volumes

Hi, I have another remedial question. I was practicing some mastering in Wavelab and the peak meter was close to 0 (where I want it). But, when I turned on an iTunes song just to compare it was much louder (SPL was significantly higher). So, I turned on a meter external to Wavelab just so I could make a comparison. The Wavelab song was peaking at about -10 on this other meter but the iTunes song was just below 0 (where I’d expect). Is there something in Wavelab after all of the meters that might be decreasing the overall output volume? Thank you for your patience with my learning.

Speaker Configuration Output? It’s at the bottom of the Master Section.

The iTunes song might have gain parameters that are used by a player. WaveLab decodes the audio at the level it is encoded, without any gain.