I think the description is wrong:

For instance if you need to spread 11 spaces between 5 words, the theoretical number of spaces between each pair of words is 2.75, yielding a total number of used spaces of 2.75 - 5.5 -

8.75- 11. Round to 2 - 5 - 8 -11 and the effective number of spaces in each block is 2 - 3 - 3 - 3.

I think *8.75* was meant to be *8.25*. Isn’t it correct?