The powder bars are made the same way. The amount of powder you can measure with each is the difference. The small powder bar is the one that came in my powder measure. When I got mine I took out the bar and compared it to the other one just to make sure. I did the same thing with the primer tube. I have learned that if two different sizes come with something it is best to check to make certain I have one of each size and then to put in the one I currently need to use. You never know who is doing the packing or if the way things are packed have changed since the instructions were written.
At least with the internet it is possible to get fairly quick help when needed. You still need to double check even that information to see if it is right.
I put a plus and minus sign near the nut to adjust the power amout. This way I know which direction to turn things when adjusting.