2. Rewriting them found errors in the Excel spreadsheets in some cases.
3. They weren't a Microsoft shop, so most/all of the experience was with an Open Source stack.
4. Most of the functionality was implemented as a series of views in the database, with a layer of reports on top of it.
5. It was easier to just pull them into our existing system as additional reports, and just have an option to export the report to Excel (which was already baked in functionality).