Many folks believe that ma ai is a fixed distance, it is not. It is the "correct distance" between you and your partner at any time during your interaction, therefore it will change through the course of a technique."
Of course your ma ai can be wrong, i.e. you can be standing too close or too far at a certain point or time. However, if you execute your technique correctly (not for one minute stating that I ever do
), there should always be ma ai between you and your partner, whether this is two sword lengths at the start (example), a few millimetres as you sweep them up during an iriminage, or arms length as you are pinning them on the ground.
My tuppence worth