You know, that sounds about right. Comey knows McCabe leaked, so getting McCabe to lie about it means Comey has some deniability plus future leverage on McCabe if Comey needs it. Very Machiavellian.
BUT....remember, Comey leaked, too via his friend the professor. So perhaps tit for tat.
Not beyond comey. He tried to sucker in trump too. The good news there is he forgot one thing never underestimate your opponent.