I assume you're self-spell checking procedure is much better for applications than it is for AF. But still, spelling mistakes can easily get job apps thrown in the garbage, or at least to the bottom of the pile. I used to review applications all the time and you'd be amazed at the spelling and grammar errors people make. One or two is okay (zero is much better), but some things are inexcusable. I assume this is to be your first job??? If so, a lack of workforce experience plus a lack of spelling skills would make my decision pretty easy.
"to since"