PT reading levels differently than other software

This is a very strange issue...

Using PT HD 11.3.1, with an HDX interface, on OSX 10.10.2

We are using a lot of waves plug-ins.

So, here is the issue:

I did som mixing on a TV-commercial, and the guys doing the animation wanted the audio delivered in -9dB.

I used L3 on the master bus, and the out ceiling was set to -9dB.

Got a call from the animation-studio, and they told me that the levels where too high, showing peaks up to -6,1dB
They had tested the audio in both Ableton and Premiere with the same result.
They even sent me a screen-capture of the audio waveform, and I could see the audio peaks they were talking about...

I took the bounced stereo file and dragged it into a new session in PT.

First of all, I couldnt see the peaks. Secondly, using the "gain"tool in audio-suite, I analyzed the audio, and it said "-9dB"

Strange!

I then imported the exact same file into Logic, and there, I could see the small peaks, and using a meter, the levels were way higher than -9dB at times.

What is going on?

I´ve been doing audio for TV and radio for 15 years, I have never seen anything like this...
I´m not sure when the problem started, but I would have heard from clients if the levels were too high, so I guess its a pretty recent problem...