This is a kirikaeshi drill. Instead of receiving, motodachi also strikes sayu men (right and left forehead) at the same time as his/her kakarite.
When you do this, both have to be aware of correctness of kirikaeshi. Since both are striking, this drill tends to be a competition motodachi and kakarite. It is not the purpose of this drill.
By having both do kirikaeshi, both can train their strength more effectively. Besides, if you don’t do this right, simply this drill doesn’t work. You have to synchronize your energy and your partner’s energy.