I have a macro program which searches through Word documents for data points
and writes them into an Excel worksheet. At the moment, it is one row per
document, with 17 columns of data per row.

One of the data points to this time has simply been a "Yes" or "No",
depending on whether certain times and charges were present or not. If they
are present, though, there are usually (but not always) multiple lines of
times and charges. I have figured out how to grab each time and charge from
each applicable line and write them to a separate worksheet along with the
invoice number (invoice number in Col A, ThisTime in Col B, ThisCharge in
Col C, TotalCharge in Col D, etc.) for each report document.

What I haven't figured out is how to sum each of these individually by
invoice number, and have those sums appear on the main summary worksheet.
For instance, the TimesAndCharges worksheet might have:

A123 2.0 45.00 90.00
A125 1.0 30.00 30.00
A125 2.5 45.00 112.50
A125 1.0 45.00 45.00

The Summary sheet would then have:

A122 ~these columns blank~
A123 2.0 45.00 90.00
A124 ~these columns blank~
A125 1.0 30.00 30.00 3.5 45.00 157.50

So I would need to:
-- identify the start and stop of each separate range on the TimesAndCharges
worksheet on the fly as the Word docs are scanned,
-- sum each range according to value, and
-- identify the corresponding row on the Summary sheet and write my sums.

Where do I start for a good approach?

Ed