criminal sentencing table

I am probably the last one to discover this but I literally was just flipping through our textbook and found something that made me go, Whoa!, I didn't know that was in there. if you look at chapter 14 specifically page 376 of our text there is a sentencing table that tshows in months the sentencing guidelines a judge must follow when looking at sentencing. the table is divided into four zone levels A-D and has 43 offense levels. Each of the 258 cells contains an upper and a lower level sentence that that judge can consult for sentencing. I don't know how informative this may be to you guys but I found it interesting.