I think you mean that you use a 40% lye concentration, which is indeed a discount from the let's say 28% "full water" lye concentration for bar soap. I think the most common is a 33% solution. Some people go higher like you do, and sometimes vary it according to their needs. My most common is 33% but I go higher or lower sometimes.
^^ same here.
I think you will find that a lot of people hand making soap tend to vary recipe liquid content according to the particular results desired. Lather boosting, hardness additives and what have you all will change the "water" to lye ratio I use.