It feels to me that the fixed extra number of meals is a far better benefit on shorter cruises than longer ones.
On a 3 night cruise for example, you'd pay the increased rate for 4 days, and get to benefit from the two extra meals over 3 nights.
On a 14 night cruise however, you pay the increased rate for 15 days, but still only benefit from the meals bonus on two nights.
It seems to me that the additional meals should probably be tiered based on length of cruise, as they are already on free at sea.