fix(billing): proper calculation of flakiness

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (8486978) 59.25% compared to head (8ecf1c6) 59.25%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #867 +/- ## ========================================== Coverage 59.25% 59.25% Complexity 798 798 ========================================== Files 214 214 Lines 4425 4425 Branches 706 706 ========================================== Hits 2622 2622 Misses 1475 1475 Partials 328 328 ```

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