Can the original Form 9 be reopened (unapproved and modified) after award and the new funds from a Form 9L be added to make the increase or does a new Form 9 need to be accomplished when doing the modification to add new in scope work?
You can either add funds by "amending" your original AF Form 9 with an AF Form 9L, Letter of Change, or you can use a new AF 9 form to add funds on your contract. It is your comptroller (budget office) and contracting chain of command's call as to what they want to do. I also refer you to another Ask-A-Professor question dealing with this same topic at, https://dap.dau.mil/aap/pages/qdetails.aspx?cgiSubjectAreaID=15&cgiQuestionID=21797
Follow the correct procedure at your installation as to which form is most appropriate for your situation.