Sports exhaust behaviour below 3000rpm

[linq]

My B9.5 RS4 has an Audi sports exhaust fitted. I noticed some time ago that when I start the engine, exhaust vapour is only visible from the nearside pipe - nothing comes out of the offside one. The engine has been running fine so I decided to ask Audi to check the exhaust when it was next serviced. The Audi technician has now told me that this is normal behaviour with the sports exhaust and the second pipe (and I assume he's referring to the exhaust pipe valve) only opens above 3000rpm or if dynamic driving mode is selected.

Can anybody else with a sport exhaust confirm this is expected behaviour on an RS4?
Thanks, Ian