that is the correct used bearing preload. you will want to use a dial style inch pount torque wrench. now the key is
that it is 15-18 inch pounds once the pinion is spinning, not the required effort to get the pinion moving. I'm attaching pics of what I use, I have setup many different rear ends. And just a word of caution, if you to the extra little pit of torque just to be sure you will wind up burning out the bearings. The bearings have seated in a certain way, if you put more torque on them than what is necessary you will wind up taking everything back apart to put new stuff in. The way I would do it is take a reading of the bearing pre-load before you pull the yoke off, keep in mind that that reading is without the differential in there. record your reading that you get before disassembly, then just match it within 2-3 inch pounds after re-assembled. there will be a touch more drag once the new seal is installed. When you go to re-install the pinion nut your going to wind up snugging it down little by little to be sure not to overload the setup.