Ryota, you need only to add a period cost for a single month in a measurement period for it to appear in an RCE report. So if you have a report for Q1 and have a period cost of $100 in January, you don't need to add period costs in Feb and Mar if the measurement of your report isn't just Feb or Mar. If you want to report on program results in Q2, even if there is no spend, you'll need to enter a $0 period cost in at least Apr for it to appear in the report. The program cost in the Q2 report will be $0. If your report spans Jan - Apr, the program cost would be $100 however.