Filtering to a specific site returns all hours worked,,

[Anonymous]

With the formula below I am trying to reflect just the hours that the site filter is pointing to. 

Hours worked =

VAR _min =calculate(MIN('TNS_dbo_POS.CPI'[Time]),ALLEXCEPT('TNS_dbo_POS.CPI','TNS_dbo_POS.CPI'[BUS_DATE],'TNS_dbo_POS.CPI'[EMP_ID]))

VAR _max = CALCULATE(MAX('TNS_dbo_POS.CPI'[Time]),ALLEXCEPT('TNS_dbo_POS.CPI','TNS_dbo_POS.CPI'[BUS_DATE],'TNS_dbo_POS.CPI'[EMP_ID]))

RETURN

FORMAT(_max -_min, "h")

[lbendlin]

to reflect just the hours that the site filter is pointing to

What's a site filter?