You can do this, and keep track of the number of rolls you run thru the stock solution. You also must add 5% (?) to the time for each roll until it reaches its limit; it should say on the package.
However, there is a much better way! depending on the film I'm using and the effect I want, I dilute a dev like X-Tol 1+1 to 1+3. This way, the dev is always fresh, I can get to my proper temp quickly by adding the right temp tap water and the tomality and highlights come out better, IMHO, with a diluted deveoper.