The ability to add a comment to a line item would be useful, so if we had a line item that was number format, the ability to add a comment eg."increased due to promotion", it gives a narrative for the value in the line item.
I appreciate that line items are not fixed (as in Excel cell comments) but this would be a very useful feature, or if there was another way, without adding a comment line to the module, which takes more space and maybe 80% of the time would be empty.