If the error goes unnoticed, it can cost hundreds or thousands of dollars before you correct the mistake. ProjectPAK has extensive error checking that reduces data entry errors. Spreadsheet estimating is not easily delegated to others. Putting out fast, accurate quotations is the life blood of every custom, quote-driven shop. You can't trust such a critical function to just anybody or just any tool.
Spreadsheets are slow.
If the spreadsheet is large or has multiple pages, this can take a while. It is built with sophisticated computer languages and runs 20-30 times faster than a spreadsheet. Spreadsheets aren't databases. Spreadsheets read and write simple PC files. This limits the supporting information they can retrieve and exploit.