The chart only depicts the movie's storyline and the movie's plotline and their ordering. It does not break out the numerous flashback sequences (with Sammy Jankis, Mrs. Jankis, and Leonard's wife). In plot order, the sections labeled 'S', '5', '6', '7', '8', 'O', '9', 'K', 'J', '15', 'E', 'D', '21', '22' and 'A' all include such discontinuities (with the flashback in section 'O' occurring in Leonard's dream). The flashbacks that occur during the color sequences are in color, and those during the black and white sequences are in black and white, with the single exception of section '22' when the flashbacks during this black and white sequence are shown in color (leading up to the linear transition from black and white to color, when the Polaroid photo develops in Leonard's hand).
Since the graph uses movie time as an axis, it does not include a timeline 3 days and 2 nights long and shows those numerous forward time skips, such as when the protagonist is sitting at a bonfire at night burning mementos of his wife, then the scene is cut to him leaving the bonfire after sunrise.
Scriptwriters/Filmmakers need to use such scientific tools to visualize their story before commenting on their film shoot. It avoids confusion at the time of the shoot, Can easily explain the scene to the artist, and is helpful for the editor in the post-production.