I think you mean:
". . . Also keep in mind that pre approval qualification letters are not commitment letters. I get most deals closed but sometimes the pre approval qualification doesn't mean anything if the buyer forgot about car loans, student loans, co-signing a note etc... "
Pre-Approval should involve an Actual Credit Report where these items will show, as well as an Employment Verification. Pre-Qualification often relies on just what the applicant feels like presenting.