I was not clear in my post that step number = count number. So I can't replay the second half.
If a step is "counted before" making the step there are still 1024 steps just as there are 1024 possible input values (counts, steps).
If you wrote the steps
adwsystems:
Step (count) 0 0 to 4.8828124mV
Step (count) 1 4.8828125 to 9.765624
...
Step (count) 1023 4.9951171875 to 5.0 V
with if statements or a case statement there would be 1024 options.
The question is what voltage do you select to output for each step. If you want step 1023=5.0V, then step 0=4.88125mV, and the ADC would never output 0V.
How is it justified to output 0V for count=0 and 5.0V for count = 1023 when each count spans a range of voltages?