As Frances says, have you consulted the original documents?

If memory serves me correctly, film 0106727 is of the "Official Copy" not the original PR.

You say your own research indicates a burial on 18 Aug 1813 but the PR (Official Copy presumeably) says 8 Aug 1815.

Where did you get the burial date?

"teen" numbers are often mis transcribed as the "1" often is hard to see and gets overlooked.

Also 3s and 5s are easily mixed up.