Depending on what device you have, the Misc Files may also include System files. Some devices separate the System files into their own category while others don't... thus, the Misc Files size will not always add up. On my Note 4 the Misc Files is a little over 8Gb and adding up the listed items don't add up to 8Gb. On my Note 10.1, the System files (System Memory) is separated out, so the Misc Files only show 1.1Gb, while the System Memory is a little over 5Gb.
As a side note, be careful what you delete in Misc Files as some of that is actual data.