Edit embedded Excel file in protected Word form

I'm trying to add an embedded Excel file to the form. Everything works
fine until I turn the protection on. The excel file is locked and
will not let me edit.

I've checked to make sure the appropriate sections are not locked when
the protection is on, and have gone so far as to uncheck all the
protected fields so essentially nothing is protected, but when I turn
the protection on the excel file is still locked.