>"==" is not a Rushmorizable expression.

Sure it is!

From VFP help:

A basic optimizable expression has the following characteristics:

eIndex exactly matches the expression on which an index is constructed.
eExpr is any expression and can include variables and fields from other unrelated tables.
relOp is one of the following relational operators: <, >, =, <=, >=, <>, #, ==, or !=. You can also use the ISNULL( ), BETWEEN( ), or INLIST( ) functions (or their SQL equivalents such as IS NULL, and so on).