Provide Aggregate/Roll up when time segment is used in calculated metrics

Currently when month segment is used in calculated metrics it doesnt roll up or aggregate tot he changed time period. For example: Lets say for some reason there was no data for a page during April 01 to April 15, and calculated metric is built with If function to populated static number (say 1000) for those days, data display appropriately with day breakdown however when date range is changed to week/month/quarter it doesnt aggregate instead display 1000.