I once worked for a company that had a spreadsheet for plant production planning. The spreadsheet was put together by a consultant, but it was not protected -

I once worked for a company that had a spreadsheet for plant production planning. The spreadsheet was put together by a consultant, but it was not protected - the company adjusted it constantly to maximize productivity at the plant. The consultant made more than the plant manager because he was the only person who understood the spreadsheet enough to make meaningful changes as required, e.g. when a machine on the line was replaced with another having a different capacity.