ignition timing ?

Hi everyone - I rebuilt my distributor with new springs,vac. can and 13 degree mechanical advance. When I set my initial to 0 deg. then run up my rpms to 2100 I show 35 deg. on my dialback timing light. When I set the initial to 10 deg. I show 45 deg. at 2100. I checked the balancer and it is off by only 1 degree. I checked the length of the slots and they are exactly the length they should be for 13 degrees. everything moves freely and all this is with the vacuum advance off and the carb plugged. Shouldn't I be getting 26 deg. with initial at 0? Thanks........