As I see it (or more important BA), you paid only 120K to get 2 tickets worth 240K, meaning you only paid for 1 with miles, and the other one is "free". So, it's 75% of 120K and 0 for the other one. Of course it depends on the interpretation of whether paying with a 2-for-1 certificate is considered free or paid ticket.
My understanding is that the OP paid 240K miles for an F US-UAE redemption (and got another one, also worth 240K miles, for 'free') .