According to MEA formula, heading should be perpendicular to a bullet path targeted using head-on targeting. It IS perpendicular movement, but keep moving straight until the wave hits, instead of turning as in orbital movement.
When there are 2 or more waves flying in your direction it becomes more complex, but Combat assumes there is only 1 wave.
If close to walls, then heading should create the longest path which would hit the wall at the same time the wave hits. Combat calculates which point in the wall coincides with waves hitting it with PPMEA. It could also be calculated with precise MEA.
The side-effect is dynamic distancing becoming hard to perform.