Divide using if , and sum result as sumx

pauliuseg 

A couple of things:

1. You should always use a well-formed calendar table. It must have full years. See here: https://dax.guide/functions/time-intelligence/

2. I would strongly recommend not to use the Auto date/time function

If you do not use the Auto date/Time function, add a new column to your calendar table with the month name and create this measure based on the one you already have:

Measure = 
SUMX (
    CROSSJOIN (
        DISTINCT ( 'Calendar'[MonthName] ),
        DISTINCT ( Service_type[Service_type] )
    ),
    [bonus payout]
)

If you want to keep using the Auto date/time function, you can use this measure, again based on the one you already have:

Measure V2 = 
SUMX (
    CROSSJOIN (
        DISTINCT ( 'Calendar'[Date].[Month] ),
        DISTINCT ( Service_type[Service_type] )
    ),
    [bonus payout]
)

See it all at work in the attached file.