Dear Mr. S. Kilmer.
My mother has a 2009 Mazda 6 2.2mzr-cd diesel, it had its DPF removed, I don't really know why but when I do oil change and refill oil, not even all the way to the top of the dipstick, after I turn on the engine so that it pulls the oil into the filter, for some reason it rises over the limit on the dipstick. Could you please explain how it works and what do I do wrong? Thank you. (also sorry for my bad English, I'm from Poland)

when doing oil changes in that, get the factory amount of oil that is removed during an oil and filter change. Then after draining it, put that amount in, then it will be correct

Thank you very much, I was doing that before but the oil level was going over the maximum line on the dipstick so I thought I did something wrong. My motor vehicle teacher didn't really know what was going on either, when I asked him that question, and he said that it might be because the DPF got removed, because apparently it's a bit different with DPFs in the first place (might be wrong, I'm not sure). Thank you again.