rev limiting on 2010 vs 2013?

roller11

I recently test drove a brand new 2013 automatic 370z non-Nismo at a dealer. Executing a full throttle, traction control 'on', red line (~7200 RPM or so) pass, the transmission automatically shifted into the next higher gear despite being in 'M' shifting mode (i.e. I did not shift the transmission).
I also test drove 2 different low mileage 2010 370Z in the same configuration (auto trans, etc) but with a very different result. Under same conditions, the engine experienced severe bogging at the same red line RPM but did not shift into the next higher gear. It was as though the engine had a rev limiter kick in so the revs would go no higher than 72-7400 RPM.
The only difference was that on the 2010 models I had traction control turned off, but turned 'on' on the 2013 passes.
Which, if either, is normal? Was there a design change between 2010 and 2013?
Comments welcome.