I've not used macros or @functions extensively either; however when I saw your post, it sounded like something an @function would do. I did a little hunting and found the @time and thought well, convert total time worked to a number, convert the base time to a number, get the difference. The difference is a time number, display it by formatting in time format. In experimenting, I did find that I had to enter numbers for hours, minutes, AND seconds (even though I might not have any seconds) to make the @function work.
If I open a new workbook, and type @time(14,25,0) and press enter, the cell shows 0.6006944 . What happens on your system?
This is what's in the lotus help files for this at function:
@TIME(hour;minutes;seconds) calculates the time number for the specified hour, minutes, and seconds.
Arguments
hour is an integer from 0 (midnight) through 23 (11:00 PM).
minutes is an integer from 0 through 59.
seconds is an integer from 0 through 59.
Notes
Use a time format to make the time number appear as the time it represents.
Examples
The formula (@TIME(13;0;0)-@TIME(9;15;0))*95*24 calculates the amount due to a consultant on a given day by subtracting the start time from the stop time and multiplying the result by an hourly rate of $95.00.
Similar @functions
@TIMEVALUE converts labels to time numbers.