I wish bio was cheaper in my area. I think one of the reasons I have experienced more regens with bio has to do with how the truck calculates soot %. MPGs aside the major set back of bio for me is oil dilution. My truck squirts fuel in the exhaust stroke during regen. Since bio vaporizs at a higher temp some of the fluid that doest make it out on the exhaust stroke gets washed back down the cylinder into the oil. This is why I have chosen to use and treat ULSD. Let me know how the 9th injector is treating you. This is one of the reasons I'm looking at a Duramax.