I was more like looking for an additional entry with a "PPLC" so it would show when I queried in the database for all "PPLC"s for all countries.
I went and matched my list of world capitals against the GEONAME and I am now proceeding with the GNA and USGS. I am working in adding all the cross references ID's to my database.
That is why you got so many entries about capitals.
Adding a PPLC entry would mean there is a city when there is none. I think for these special cases it is easier to handle them separately as you already did. It would be too confusing to use the 'normal' way of dealing with them.