SUMIFS with Multiple Criteria with Multiple Values

There are certain situations where SUMIFS returns values I do not expect when there are multiple criteria. Can you help me understand what is going on here and how I can get the expected result?

This screenshot shows the data I am using, the values I get, and the values I expected to get:

The data is in a table called "Table1". Here are the four formulas I am using:

=SUM(SUMIFS(Table1[Value],Table1[Letter],{"A","B"},Table1[Greek],{"Alpha"}))
=SUM(SUMIFS(Table1[Value],Table1[Letter],{"A","B"},Table1[Greek],{"Kappa"}))
=SUM(SUMIFS(Table1[Value],Table1[Letter],{"A","B"},Table1[Greek],{"Alpha","Beta","Kappa"}))
=SUM(SUMIFS(Table1[Value],Table1[Letter],{"A","B"},Table1[Greek],{"Alpha","Kappa"}))

The first two statements work as expected, but when I add multiple options in the second "criteria" then the numbers don't add as I expect them to.

In the third statement, for example, I would expect that it adds up the first four rows (everything with (Letter A or B) AND (Greek of Alpha, Beta, or Kappa)) which would total 70. Instead it comes back with 10.

Using Excel 2010 on Windows 7.