SAT Incorrect Answers as Additional Section/Bookmarks

I have recently noticed that when I miss questions on both ERW and Math, they are usually under the same sub-sections that I usually miss (for example: interpreting linear data, percents, etc.). Sometimes the skill level will go from a 4 to a 3, but most times it does not. I think it would be really helpful if we could bookmark certain sub-sections we want to review more. These "bookmarked" areas could show as the same way the math, ERW, and essay review areas show up. With the bookmarked section, I also think that Khan Academy could put add sections the user frequently misses. This way, the user knows for a fact what they need to improve. If I had a specific area that told me what I miss instead of having to go through past practice tests, studying would be much more efficient.