eazyBI by default sum any values per particular dates. You can get the Sum of SOWTotalHours with SOWStartDate or SOWTotalHours with SOWEndDate by default. You would need some calculation if you would like to split SOWTotalHours between SOWStartDate and SOWEndDate.
You can use the MDX formula. It might be more appropriate if this is for a one-time report only. This, however, might work slow. You can consider using the calculated JavaScript custom field for importing this as a new measure.
Here are two community posts with some example solutions in this:
The first one includes two options - using calculated MDX formula and JavaScript calculation based on default fields - issue created date, due date, and original estimates hours.
Another example uses the MDX formula with a custom Target start date and Target end date with Original estimated hours.
You can use any examples above and substitute the dates with your start date and end date. Please use measure SOWTotalHours crated instead of Original estimated hours.
Daina / support@eazybi.com