1) are the plans the same? even with 2012 I believe the optimizer and engine have limitations about index usage and good plan formulation.
2) have you tried pre-computing the areas of each object and accessing that directly? That should remove part of the performance issue during query runtime if I understand the need correctly (the denominator looks to be the full area of table 2 object).
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service