The reason for small differences like that you are referring to is because WHICH alignment pattern you choose (Loefgren, Baerwald, etc.) has not been standardized. On the WallyTractor, the nominal dimensions of the arcs are MOSTLY quoted in Baerwald, but each arc is a SET of two options - Baerwald or Loefgren. Depending upon the total radius, the difference between the two can be anywhere from 0.6mm to 0.22mm.
So...your Tosca arc is on the WallyTractor but they may have called out the Loefgren arc when I named the Baerwald arc. They are concentric with each other so when you look closely, you'll see the dual arcs. Whichever one you choose, the IMPORTANT part is to ensure you use the proper null points for the cantilever alignment.