As of this morning all scores affected by an inaccurate scoring algorithm have been corrected. 
There were 20 total quizzes affected causing some users to be graded close to 3% low. Once the issue was found, the correction was created and applied followed by extensive testing to verify nothing was missed. We are very sorry for the error and inconvenience. We have instituted a means to avoid this issue in the future. Thank you for your patience!