In the 5500-SF instructions, "What to File", it says, "Plans required to file an annual return/report that meet all
of the conditions for filing the Form 5500-SF may complete and file the Form 5500-SF in accordance with its
instructions."
There are a lot of "musts" in the instructions, but here they use "may". Is there any reason a small plan filer that is otherwise eligible to file a 5500-SF cannot choose to file a 5500 with Schedule I?