My 22 3500 HO DRW went 1,410 miles on 2.5 gallon of Blue Platinum DEF this past fill up. EVIC fuel economy says 14.7 mpg average. Thats 90%+ highway driving at 75mph in an unloaded / not towing configuration. Works out to about 2.5 - 2.6% DEF to Fuel Consumed which is right where it’s supposed to be. Slightly elevated consumption due to the higher speed but well within the realm of normal. I’ve had Y43 completed for several months and have noticed no issues or changes in DEF consumption or Fuel consumption. What I’m calculating now is about the same as what I calculated prior to having it completed. Based on everything I have studied on this and experienced myself, I don’t see how Y43 would have any impact on DEF consumption. I would be more inclined to believe that variation in consumption is more readily attributable to operating conditions, duty cycles, variations in the DEF itself, and potentially variations of the fuel consumed.