I found a semi-workaround because I embarrassingly was having trouble adding the new entry I wanted to the iniReadSection array.
I captured the existing entries with iniReadSection... Deleted the section with IniDelete... Recreated the section name with FileWrite, added the new Entry with FileWrite, then dumped the captured array underneath it with FileWrite.
$sIni = "Scriptsmenu.ini"
$Sec = InputBox("Section to edit", "Section:")
$New = InputBox("Entry to add", "Entry:")
Local $var = IniReadSection($sIni, $Sec)
IniDelete($sIni, $Sec)
Local $file = FileOpen($sIni, 1)
FileWrite($file, "[" & $Sec & "]" & @CRLF)
FileWrite($file, "Item=" & $New & @CRLF)
For $i = 1 To $var[0][0]
FileWrite($file, $var[$i][0] & "=" & $var[$i][1] & @CRLF)
Next
FileClose($file)
I'm still pretty bad working with arrays. I can create them from scratch, or pull them from something like iniReadSection. I run into serious trouble when I try to tinker with adding something to an array after it's been created.
This solution will do for now, but if anyone can easily explain how I would add an extra value to that iniReadSection array I'd love to know how to do it in the future. This would also probably make alphabetizing the section much easier too (I'm guessing?).