Are you also using the M1 oil filter? You could look into the filters that use a synthetic media on the inside (amsoil and royal purple).
My iron was 16 @ 4,404mi with a pure one filter; 20 @ 4,979mi with a M1 filter; and 18 @ 4,660mi with a K&N filter. Since you used the oil longer, the wear will show which seems normal. On BITOG, iron increases linearly with the increase of usage of the oil. My aluminum was 4-5 range with all three tests.
Change to a different brand of oil and test again. Changing your at every 6K miles is a safe mileage with no ill effects.
Here's my reports:
View attachment 8356