From the Encase link provided earlier:
* Light-gray squares indicate a Last Accessed Date/Time stamp for a file.
* Medium-gray squares indicate a Last Written Date/Time stamp for a file.
* Dark-gray squares indicate a Creation Date/Time stamp for a file.
* A square will be blue when the file’s checkbox is checked.
* A square will be red when the file is highlighted.
If you are working with the same black and white scanned image I am, what indication is there that there are clearly 3 shades of gray with no blue and no red? Actually, I can only make out two shades of grey or gray and black. But any number of boxes could be red or blue and would show up as black wouldn't they?
Also, if she were transferring files from the desktop to the laptop then the laptop should have at least as much activity during that given hour as the desktop. The 2-3 slot has more activity shown on the desktop than the laptop, the desktop, very little use during 3-4. So, I wouldn't say she is simply transfering. She would have to be putting it onto a flash drive, if this is what she was doing, during the 1st hour, then putting it onto the laptop during the 2nd hour. If so, why weren't these types of devices included in the search?
Another observation that may or may not be helpful...
The longest column has 99 rows marked. There are about 125 rows available on the screen. If each box is a file then this would be 297 files for the 99 row column and a potential to show 465 files accessed or created during any given hour. So, would this mean that there were over 465 files active during the hours with 3 dots?