Calculate with Filters from different columns

So thanks to DataInsights I've been using the following to calculate the average based on mulitple filters from a single column in a table. However i'm now trying to figure out how to find calculate the average based on two conditions from two columns in the same table shown in second code segment.

Measure =
CALCULATE (
    AVERAGE ( Combined[Response Time (Days)] ),
    Combined[Type]
        IN {
        "CT - Change Request (10)",
        "CT - General Support (5)",
        "CT - New Implementation (10)",
        "CT - Technical Issue/Fault (10)"
    }
)

Here is an example of what I've tried, I've tried others as well however it either displays 'blank' or the code errors.

Measure = 
CALCULATE (
    AVERAGE ( 'CT Combined Extracts'[Response Time (Days)] ),
    'CT Combined Extracts'[Type]
        IN {
        "CT - Technical Issue/Fault (10)"
    },
    'CT Combined Extracts'[Service]
        IN {
        "CT - Case Access"
    }
)

Any help would be much appreciated.