I have a worksheet configured as a timesheet, where each row represents a
task performed. For any given day, I track the task(s) performed and the
hours spent on each task, and there are many functions in the worksheet.
The worksheet contains the following columns:
Column A: blank column (not used for anything).
Column B: series of dates (with a blank row in between each date).
Column C: tasks performed, manually entered.
Column D: hours worked on the task.
Column E: hours worked for the week. There's a function in each cell where,
if it's Sunday, a sum of the week's work will be displayed.
Column F: hours worked for the month. There's a function in each cell
where, if it's the last day of the month, a sum of the month's work will be
displayed.

Here's my problem: Whenever I add an extra row (in order to display
additional tasks performed that day), the function in column E changes. It
starts off as:

=IF($B18="","",(IF(WEEKDAY($B18)=1,(SUM($D$9:$D18)-SUM($E$9:$E17)),"")))

.... but when I add a new row, the function in that new row ends up as:

=IF(WEEKDAY($B19)=2,SUM($D$9:$D18)-SUM($E$9:$E17),"")

How can I ensure that the functions in the new row follow the same
conventions as in the row above? Thanks very much.

Gregg.