Google Analytics: Exit page report differs from conversions

I have an issue determining my checkout pages exit percentage.

Looking at the site’s database event information for a single day I am given the following information:

  1. Entered checkout – 306
  2. Completed Checkout – 249
  3. 81% completed (completed / entered checkout)
  4. 19% exited (remainder)

When I look at my reporting in Google analytics I am given the following information:

  1. Entered checkout – 304
  2. Completed checkout – 247
  3. Exits – 26
  4. Exit % – 0.09% (exits / entered checkout)

So what reason would there be for my Exit % to be different than the math between the difference of entered and completed checkout?

Thanks in advance!