Calculate function not filtering when a variable is used.

Echoing Greg_Deckler on this one, but with a little more information. Variables are calculated only once and then stored only once and cannot be re-used in their current context. The only exception to this is if you create a variable that is a table: 
ie. VAR _SourceTable = FILTER(ALL('Date'[Year]),'Date'[Year]>=2010) 
and then later on you want to further filter this source table ie. VAR _MoreFiltering = FILTER(_SourceTable, [Year] >= 2013).

Measures are calculated in the current filter context (sometimes that's okay if you want to keep the value static) but you can't use CALCULATE() to adjust that after the fact.