Hi,
Sorry for late answer but reply option is not working.
Starting from cage 1, the unique sums are growing. For the example, if the sum of the numbers in cage 1 is 5, than in cage 2 the sum must be at least 6 or higher. Total number of cages in the competition puzzle is clearly visible.
Nikola Zivanovic
Competition Director,
WPF Sudoku GP 2017