That was my thinking as well. In the ongoing use of HPL in my wife's Volvo XC (which is nearing 300,000 miles) I will continue to monitor/examine the filters at each change. I am curious to see when/if the carbon settles down as it has in Wayne's Durango.
The XC had a previous owner who changed it at the dealer until we bought it at 90,000 miles. The dealer, sadly, in those days, used bulk dino 5W30 (Castrol) which didn't meet specs. Many Volvos were ruined by Volvo NA not following the actual Volvo oil specs, and just using the 5W30 viscosity on an extended drain.
So, the engine in the Volvo had some deposits from that period in its life, and despite running on Mobil 0W40 and other Euro spec oils over the subsequent 200,000 miles, there are still some deposits in the engine. I suspect that it will take far longer to clean up than Wayne's Durango.