Add cells in pivot

Hello,

I would like to create a pivot table based on a web query where the output
of an estimate field is:

1 week
2 days
2 days
1 day, 4 hours

I want the pivot arranged so that items are grouped by version then resource
so that I can see how much work each resource has for the version.

Is it possible to have Excel add values such as the above in a pivot to
provide a total amount of work? I think not but wanted to check with the
experts.

I currenty create this pivot by exporting the data from the web app to
Excel. When exporting, the estimates come out in seconds and I created a
calculated field to deal with this.

The web query output comes out as above, however. Driving the pivot from
the web query will be easier if I can add the estimates without conversion or
helper columns.

Any help is appreciated, thank you.

Tom