Formula should be flexible to allow custom start (date and time) and end (date and time), so I can define my week for eg. mon-sun, or sun-sat etc...

Question #2 is there way to make report to drill down to level 3 on start? I would like to have parameter which allows to switch view from "summary view" (level zero) to "detailed view" (level 3)?

Thanks all who try to help.