Distinct count of only the minimum value

amitchandak , your response although not the solution, guided me through the right path.
The key here was the VAR selValue which applied the correct context when used in a Matrix and replaced the SUM for a MIN.

Also, I didn't hard code the value "3", in its place I used a parameter. 

Here is the final DAX that did the trick:

DCount GUID min with parameter = 
VAR selValue = SELECTEDVALUE('Append'[Standard Value])
VAR Calc= 
    COUNTX(
        FILTER(
            SUMMARIZE(
                ALLSELECTED('Append'),
                'Append'[Employee GUID],
                'Append'[UniqueID],
                "Min", MIN('Append'[Standard Value])
            ),
            [Min] <= [Parameter Value] &&
            [Min] = selValue
        ),
        [Employee GUID]
    )
RETURN
Calc