Do I need to do the def dissonance for lower levels?

I haven't unlocked the Dissonant Echo lab yet; is there any point in doing the defense disso for the weaker tiers before I unlock the lab? I feel like it will ultimately be a waste of time that I could be using for my farm runs. I understand that I SHOULD get my defense bonus up for what I'm farming (t10 is netting \~275T+ @ \~10.5hr), and I am working on making t11 my primary farm, so, until I get the echo lab, does it matter if I leave the lower levels untouched?