The issue with dilution "B" (1:31) is it gets the times down in the iffy areas of 5 minutes for some common films.
That's where dilution "H" (1:63) came from. You can just double your times.
It makes mixing a little easier as I just go 10 ml straight syrup to 630 ml H2O.
Works for me. I used to use a lot of it but went back to D76 1+1 for my everyday stuff.