You might want to read on passive regenerations. A passive “regen” is when the DPF burns off soot due to higher engine loads and exhaust temperatures. It requires no intervention from the motor or ECU.
If a vehicle's exhaust keeps reaching temperatures to burn off soot through enough load, they would not get to the stage of 80% accumulation for active regen to happen.That’s not how the emissions system works. The DPF accumulates soot until it reaches its capacity and then performs a regen to burn off the soot. The Eco Diesel typically goes into active regen mode at about 80% Soot percentage and will drop down to 10 or so % after it completes the regen. My ZR2 Bison Duramax goes into regen at 100% DPF capacity so all are different. Point being is that the engine must regen to burn off soot.
Passive regen - soot being burned without intervention while driving with enough load to get to high exhaust temps.
Active regen - soot being burned off due to ECU intervention if it reaches 80% soot accumulation.
Forced regen - when either of the above two modes fail.
That is my understanding.