Sounds like your vacuum tube is hooked to full manifold vacuum on the carb.
Should be to "ported spark" tube on carb, which is above the throttle blades.
If the carb is adjusted properly, you should not get a measurable vacuum signal out of the tube at idle.
So if you hooked up the advance, there should be no (or very little) change in timing.
Double-check the port location.
And like was said, if the distributor was installed off by a tooth or four, they probably just put the wires where it was appropriate. Happens when someone doesn't feel like taking the time (or doesn't know how) to re-align the the oil pump shaft so that the gears mesh and the hex shaft lines up.
The position does not matter as long as the rotor lines up with the right one and the rest follow suit. And your vacuum advance can doesn't hit anything.
A good reason to put it where the picture says however is for consistency and to match up correctly with a distributor cap that has the number "1" molded into it.
Paul