The difference between the calculators come from tyre size. Calculating the circumference of the wheel with inflated tyre is somewhat inexact. My personal favourite method is to take the rim bead seat diameter and add twice the tyre width to arrive at the ultimate diamter, from which circumference is calculated. Obviously if you use different width tyres, the gear inches will change.

A simple sanity check is to take the gear range, ie the ratio of the highest to the lowest gear:

95/26=3.654

and compare with the sprocket ratios:

28/11 * 56/46 = 3.099. clearly the two are different.

Assuming a 32 tooth cog:

32/11 * 56/46 = 3.54, still not the same as the spec.

Assuming a 34T cog:

34/11 * 56/46 = 3.76, still not the same.

I still say the 95/26 is wrong.