How about something like this?
The image, below, is a table where the first column is called 'date'. After you pick the date for row 0 (highlighted in yellow), the dates for the previous 7 days are calculated. The nice thing is that FormCalc takes care of calculating the dates correctly.
// form1.page1.subform1.table_.row_[0].date::exit - (FormCalc, client)
var dayNum = Date2Num($.formattedValue,"MM/DD/YYYY")
row_[1].date.rawValue = Num2Date(dayNum-1,"MM/DD/YYYY")
row_[2].date.rawValue = Num2Date(dayNum-2,"MM/DD/YYYY")
row_[3].date.rawValue = Num2Date(dayNum-3,"MM/DD/YYYY")
row_[4].date.rawValue = Num2Date(dayNum-4,"MM/DD/YYYY")
row_[5].date.rawValue = Num2Date(dayNum-5,"MM/DD/YYYY")
row_[6].date.rawValue = Num2Date(dayNum-6,"MM/DD/YYYY")
Steve