He might just mean the Chord is in A and needs to be strummed harder? But then It's down to the song. So who knows.
What he meant is you are playing the exact same notes, just on a different place on the fret board. You were playing the 3rd, 5th and 7th fret on the E string. What he meant was if you were to play the 3rd fret on E as you were, then move onto the A string and play it open, and then move to the 2nd fret on the A as well, you will be playing the same notes as before, in the same octave, just in a different place, it means less moving around the fret board, or personal preference. It will all make sense soon, promise!