If you did the setup correctly, locked timing at 12* then verified with your timing light the distributor is where it needs to be. Once done with that step you need to unlock the timing so the computer can control the timing. If you Look at my pictures above you can see the rotor looks as you describe yours. I have my timing set @ 22* @ idle and 32* total at 3K rpm with some vacuum advance added. Make sure your timing is working. Most likely your going to have to get the adjustable rotor as discussed above to make it work.
Also when you make changes, clear the self learn as per the instructions.