I have a macro that I use to subtotal lines (I took parts of this from
other macros on this group and elsewhere and don't know who to give
credit to, so thanks whoever you are)

Sub SUBTOTAL()
'- select range and run macro
Dim MyRange As Range
Set MyRange = Selection
ActiveCell.Offset(MyRange.Rows.Count, 0).Formula = _
"=SUBTOTAL(9," & MyRange.Address & ")"
ActiveCell.Offset(MyRange.Rows.Count, 0).Select
' moves to bottom of selection where subtotal was just inserted.
End Sub

As an example I have numbers in B1:B10, I highlight from B1 down to
B10, and hit a button to run the macro. It puts the subtotal in B11.
So far so good.

If I highlight from B10 up to B1, it puts the subtotal in B20.

How do I amend so that I can have it work no matter where I start to
highlight?
Can I do it to subtotal across, and total on the right? And even
better let the macro know if it up/down or across and put the subtotal
in the right place.

Thanks so much.