Topgolf $15 off reward

Has anyone used this reward? T&C says it is limited to 2 per myVIP player. Does that mean you can use 2 at once to get $30 off? And it says booking ahead is not required, but is there a way to book ahead if I want? If not, it seems that the discount for booking ahead would be worth more $15 and this is kind of a pointless reward.