Incorrect calculation of $certificate->progress

Hi All,

We use this module in our current project and it works quite good. But unfortunately calculation of progress doesn't work well.
I'm working on integration of this module with Views and I found that when several quizzes are linked to certificate, the process is always 0, except the situation when all quizzes are passed. I found that the issue is in this code:

  // Quiz calculations
  foreach ($certificates as &$cert) {
    $cert->gotpoints = 0; // Points the user actually got
    $cert->gotpoints_capped = 0; // Points the user actually got, capped to points needed for each condition
    $cert->needpoints = 0; // Ponts the user neede to pass
    $cert->totalpoints = 0; // Total points available
    foreach ($cert->quizzes as $quizvid => &$quiz) {
      $cert->gotpoints += $quiz->score->achieved_score;
      $cert->needpoints += $quiz->score->pass_score;
      $cert->gotpoints_capped = $quiz->score->achieved_score > $quiz->score->pass_score ? $quiz->score->pass_score : $quiz->score->achieved_score;
      $cert->totalpoints += $quiz->score->max_score;
    }
  }

Calculation works well with this quick fix (I added "+=" instead of "="):

$cert->gotpoints_capped += $quiz->score->achieved_score > $quiz->score->pass_score ? $quiz->score->pass_score : $quiz->score->achieved_score;