Dr Jay and Al Fadi continue the comparison between the upper and the lower layers of the Sana manuscripts of the Quran with the 1924 Hafs edition of the Quran. They point out differences that changes the meaning of the text; for example Sura  9: 9 in the lower layer of the manuscripts states" the way of Allah while the Hafs Quran of 1924 says 'His way".  Another difference in the upper layer  as an example is Sura 7: 76 "you directed vs he directed" They point out that most of the differences have to do with the diacritical marking which did not exist until the 8th century.  Even with the upper layer of the manuscripts there was no standardized Quran yet.