Never attempt to create formula groups based on Excel's shared formula ranges.

Because they are wrong more than half the time.

Change-Id: I24e49c53520442be698e43976d28d0f8477648e6
(cherry picked from commit c6ccab60fa881ad80e64168ced4c5f74349512b0)
Update the comment & use the column position of the last formula record.

Change-Id: I877ec2153754328781e5d87b8eca47998b70fa22
(cherry picked from commit 5a295eb97b9461e603c723308135c1477846e839)