What’s going on with the grading of the 1958 centavo?

Obverse of the 1953 (left) and 1958 (right) centavo coins. 
Note the difference in the level of detail, most notably in the waves of Marti’s hair.

Coin grade distribution for 1953 (blue), 1958 (red) and average 1C (gray) from both NGC (left) and PGCS (right). The average 1C was calculated by adding the population of all 1 centavo dates. Note the bump in 1958 AU coins much higher than 1953 and the average. 

Question 1
Edge view of NGC graded fine reeding (left) and coarse reeding (right) varieties. 
Note the difference in the number of reed in between two prongs.
If you still have unanswered questions, please leave your question/comment below and we will add our answer to the list of questions above. 

The story behind the 1953 Jose Marti Centennial series

Original design proposed by Dr. Esteban Valderrama sharing the same reverse design. The coins on the right were offered for auction by Heritage Auctions in September 2018.
Original design proposed by Dr. Esteban Valderrama for the centavo piece (left) and an alternative design proposed for the reverse of the 50 centavos piece (right).
Question 1
If you still have unanswered questions, please leave your question/comment below and we will add our answer to the list of questions above.