The "regen once per tank "is such a generic term that all brands are using for reference to regen intervals. My 6.6L had a 136 liter tank, regen was every 450 kms( i rarely drive in a city by the way), about 3/4 of a tank. My Cummins regen was every 300 kms or every 1/2 tank same driving habits and 130L tank. My 2.8L regen is every 650-700kms , 3/4 of a tank, tank size 80L. So you can see that referring to regen as once per tank by all brands is never accurate or a good reference point.
In the city with stop and go traffic and idle time will definitely affect regen cycle. If you work the truck hard, pull trailer, drive up steep grades, do lots of highway driving you will get the best milage between regens. This is due to the truck performing p
Passive regens due to the heat in DPF cleaning without having the 5th injector dose fuel(Active regen)to provide the heat. When driving short trips or slow city driving the DPF cannot do passive regens and active ones are more frequent to deal with this kind of driving.
2016 Canyon CCLB 2.8L Duramax. SLT Nav/bose, driver alert,rear slider.