SGE:
I agree with your assessment. My work always involves working between multiple sub-projects on a daily basis. Each one has an alphanumeric code assigned to it, and that code was entered into a networked time-tracking software application along with the actual time spent on each, in quarter-hour increments. The networked aspect of it made it easy for anyone to "see" a snapshot of where the time-spent totals were for any sub-project at any given time. This was standard operating procedure and was very easy to carry out. Our end-of-year auditing was also simplified by this software-based tracking system.
Cheers,
DG