I believe that you have correctly set your meter.
With an EC meter, the electronics in that meter has no tie to ppm. EC is just a small electrical current that is run through the water from one point on the probe to another point.
What you are actually measuring is the ability of the solution to conduct electricity. If you have pure H2O, then electricity will not conduct through it (like ground water or tap water). When you add chemicals to the water, you are disolving chemicals (into a solution)that will conduct electricity. You are effectively building a bridge through the water for electricity to travel. The greater the concentration of chemicals, the bigger the bridge.
The bigger the bridge that is created by the chemical concentration, the more electricity that flow across it from the starting point on the probe to the recieving point on the probe. The meter is able to read this flow of electrical current and tell how much is flowing at any given moment. That is why if you hold the meter still you get one number, and if you swirl the meter probe around in the solution, that number goes up. It is running into more of the electrically conductive particals of the chemicals added to the solution.
It is very similar to taking a "volt/ohm" meter and checking the resistance in the water, and giving you a readout in a number. On the EC meter that can be calibrated, This allows you to adjust the number output to correspond with a preset ppm that you require. In this case you are setting the meter to correspond a reading of 2.0 with 1000ppm.
I think you could have as easily set it to 2.0 corresponding with 2000ppm.(setting it that high tho might make it less accurate at lower readings..not sure) I have a Hanna TDS meter that does exactly the same thing but the difference is that it was preset at the factory to give me PPM.
If you take a close look at some of the different nutrient brands(feeding schedules) you will see that they give the required nute levels in both ppm and EC. You could as easily go by just the EC reading and correspond that to the nute regamine from the manufacturer schedule. However, since you have calibrated it to 2.0=1000ppm, you are able to follow the nute schedule in either ppm or EC.
If your nutes brand gives you information on the bottle or schedule in ppm rather than EC, you are set to proceed.
I hope I haven't just confused you with the "science" of measuring the Total Disolved Solids(TDS) but I wanted to give you a better understanding of what you are actually measuring.
