Hi Claire and welcome to the forum,

The higher number is correct. See if using a pivot table works easier than a formula. If you want you can base the Pivot on a Dynamic Named Range so it will reflect what is added or changed or removed from the table. Note also Pivots need to be refreshed after data is changed. See the attached.

You can change, add or remove stuff in column A and the Pivot will automatically reflect the new data. Look behind the worksheet at the VBA, at the Names Manager for the DNR and the source of the Pivot data.
Tally Times by Hr Pivot with DNR.xlsm