ATB saw tooth layout and Table Saw alignment?

I started to align the contractor’s saw today. As I was using a dial indicator in the miter slot to verify that the saw blade is parallel to miter slot, I noticed an unusual thing. As I slide the dial indicator’s tip across the side of a carbide tooth the dial indicator changed its reading by a 2 – 3 thousandths. So when I take a measurement with a given tooth at the front of the saw, rotate it to the back of the saw and take a measurement, my measurement could be off based solely on where I placed the pint on the saw tooth

Here is a diagram (I am not an artist):

As I slide the dial indicator from point D to point E, I will notice the 2 – 3 thousandths change.
So if I make a measurement with the point at E on the front of the saw and then rotate the blade to the back, if the dial indicator’s point lands closer to point D than E, how do I know if the difference in reading is an alignment issue or the angle on the carbide tooth?

The specifics:
Delta contractor’s saw about 20 years old
Forest WoodWorker 2 ATB blade bought along with the saw.
Blade sharpened twice. Last time by a New York (?) company offering free blade sharpening at the WoodWorkers show.
SuperBar and it’s dial indicator.

-- Jesse, Saint Louis, Missouri