If i'm going to use Excel, i'd rather see additional field which tell type of the data so i could filter/sort it with less effort.
This an interesting point. When designing this I considered it to be more work for everyone manually editing files to add a 3rd field, which in addition increases the export file size without aiding the parsing of the file in any material way (given it's currently possible to disambiguate from the reference alone).
That could work, but in such case user need to know possibility of creating new field either using excel formula or macros. Export file size shouldn't be concern in century 21 unless we're talking about printing CSV file.
Further, it creates additional complexity and increases the potential for mistakes due to typos.
Do you mean wallet developer or user?