No cover of blood tests for Down Syndrome screen

As per the Momentum policy for my medical plan (Incentive Option), I am covered for the cost of the growth scan and assumed that, as the blood tests were necessary part of this scan, that these would be covered too. So, imagine my surprise when the claim for the blood tests was submitted to Momentum by the service provider, and Momentum only paid out R248,00 of the R1403,70 total on the grounds that my \benefit limit had been exceeded". In my opinion"