So according to your logic, any imperfection of memory is the sign of a criminal. All innocent people have perfect recall, and never get confused on the witness stand. Even when questions are asked in a way intended to lead to confusion.
Do you believe that Jesus comes down from heaven and help the innocent get everything right?
Get a clue. Amanda doesn't remember calling her mother at noon before anything had happened because there was no such call. That the prosecutor claimed such a call happened doesn't make it true.
On a related issue, all of Amanda's phone calls made after the murder was discovered were tapped and recorded. When she met with her lawyers in prison, the conversations were recorded. Her cell was bugged to capture everything she said. Her parents and relatives phones were tapped. The same thing was done with Raffaele and his relatives. Yet in all those hours of recordings, the prosecution could not find a smoking gun proving guilt. All they came up with was trivial differences in how people remembered what happened.
Anyone who has studies witness accounts knows that such differences are normal. We don't have a TIVO machine inside our head that will play back exactly what happened. One would think that anyone who made mistakes on a school test would realize that memory isn't perfect. Yet all too often in a discussion of a criminal trial, we run into the assumption that perfect recall is the norm.
A skeptic should know better.