Video Looping mode confusion

Help me understand how it works/ is supposed to work.

The manual says
"The most recent footage is saved on the memory card, up to the number of minutes selected in step 2."

When I set to Loop 5minutes. It recorded a longer than 5min segment, followed by many 1min video clips of the entire drive.

When I set Loop 10 minutes. It recorded a 19min segment, followed by many 2min video clips spanning the entire drive.

Each time it seems like I *should* have had only a 5min and a 10min clip respectively.