This is new technology so I am not sure that there is anything wrong with the way it is performing. I bought this Kubota after owning 2 New Hollands neither of which had a DPF system. I am sure that Kubota makes a great product or I would not have taken the chance. I make a living with these things. I burn low sulfur off road diesel. I appreciate you mentioning this I might try a little test on my own and burn on road fuel for a little while to see if that changes things. I will keep on posting the information for all to see. I hope this helps others in the future. I myself have been appreciative of information I have found on forums many times. (Just don't do a lot of posting usually)