Aftertreatment Outlet NOx reading stable - Reading Not Available

[RollinCoal]

Cummins recommends "cleaning" the filters every 450k
Personally Id swap it out
And replace diff pressure sensor, exhaust pressure sensor at the same time
those are what tells the ecm when its loaded/full
Id also suggest doing a tuneup at the same time in replacing egr diff pressure and cleaning the ports then replace intake pressure sensor