
You haven't quite understood the hip-scores, I'm afraid. You don't combine the scores of both parents - they both have their separate hipscores which is a combination of the score of left and right hips, and ideally only breed from parents with a score of less than the breed average.
For Newfoundlands the average score is 27, but the median score (the most common score) is 19, so in an ideal world only those scoring less would be bred from. What were the individual scores of the sire and dam?