IF Condition with Date in Table

IF Condition with Date in Table

I'm working with a table that has invoice data where the dates are formatted as 04/05/2016 MM/DD/YYYY

I'm trying to conditionally apply a fee structure using a formula column, but I can't figure out why it's not working. 

IF((INVOICEDATE>date( 02/01/2016)), (USERS*10),(USERS*5)

The expected behavior is: If the invoice is dated after Feb. 1st 2016, the fees charged are # of users * $10, otherwise it's the # of users*$5.  The above consistently evaluates as *5 suggesting I've got something wrong on the date formula, but I've also tried to represent it as (2016,2,1) and (2016,02,01) and (2016;2;1)  

Any pointers on what I might be doing wrong?  

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