Frequency chart would make sense if all you had was the pitch or frequency of the oscillator, but we have chromatic mode and can actually select the note of the trig, unlike (IIRC) the MD which only has pitch/frequency. And the AR does a pretty good job of staying accurate when played chromatically on the pads or even from an external keyboard.

If you like to go by the numbers it might just be easier to program in chromatic mode – that way you can hold a trig and select the note on the pads for visual feedback.