Do you mean that the column for “% Saving Against Benchmark” in the recommendations page is showing zeros? But the GWP savings is showing a minus value? If that’s the case, it just means that you have not specified a benchmark design in the ‘Details’ tab of your design. You can scroll down the drop down list to select your base design under ‘This Structure’.
However if the GWP is ALSO showing zeros, then there must have been a mistake during the recording stage of the recommendation.
Hope that helps!