Excel Data Outlining

[Stangard]

I have a spreadsheet that organizes data into an outline. When I expand
an outline group to edit the data in the cells I have a button that,
when clicked, writes the date the changes were made to the row. I only
want to process the expanded rows when the "process Updates" button is
clicked. I can't figure out how to detect whether a row is expanded
outline range of rows to set the date. I have tried to use the visible
and hidden properties but can't seem to find the correct command that
will let me test them.
Here is what I have tried so far trying to get te row numbers that are
visible when an outline is expanded.
Private Function GetRange() As Range
Dim Rng As Range, RowNbr, temp, s
AutoFilter is on
Set Rng = ActiveSheet.AutoFilter.Range
RowNbr = Rng.Rows.Count
Set Rng = Intersect(Rng, Range("A:A"))
Set Rng = Rng.Offset(1, 0).Resize(Rng.Rows.Count – 1
RowNbr = Rng.Rows.Count
temp = Split(Rng.Address, ",")
'Set GetRange = Rng 'sets the array to the visible rows
Set GetRange = Rng.SpecialCells(xlVisible)
RowNbr = GetRange.Rows.Count

'Set GetRange =
Range("Task_Table1!_FilterDatabase").SpecialCells(xlCellTypeVisible)

End Function
I am able to pull out 36 address ranges but if I have more I only get
the first 36. I haven't found anything that says the
specialcells(xlvisible) properties have a limit but it is very
repeatable with the commands above.