Impact or Melee?

[mceochaidh]

Often there seems to be a choice for BGs locked in melee to fight against more than one enemy BG. I see the red arrows giving a choice. If choosing an enemy would require the friendly BG to turn, I assume that this still counts as a melee and not an impact. Does anyone know for sure?

Is there any penalty on the turning friendly BG? Often the BG turns and offers a flank to the enemy BG it was facing. The friendly BG does not always seem to be able to turn, just some of the time.

As an aside, I do not think, once a BG is loked in a melee, it should ever be able to turn, but should fight the enemy to it's front that it charged into to begin with.