We were on the wrong tracks...
//
Yes now i get the question.
I tested it with pretty large files to import and it was fine. (you should make a backup before, well this program makes it too, but to be sure).
You can make one file that contains many Objects (or one file that contains many Definitions) and import it, then there is no need to add them one by one.
DCED works the same way but it cannot handle Def section as it should and this generates "rubbish" at the end of Def section (end of file) and DCED cannot correct the Def section size and it can result in unreadable file (Objects have no Def-s, example imported vehicle is only visible, hangs in the air and player cannot use it).
And you could only use this program to correct size values, maybe if you work with Hex editor and bored to make corrections, that is for i used it.
And yes you can use it many times, select Load to load the Actors.bin then select Add, select file to import, then click Save. On statusbar it shows what has been imported, after it numbers must change, (if imported def file was with data of 2000 then new Def value is old value+2000).
I guess you know this correctiong theory (in post 19)
link \o/http://www.rprclan.com/forum/22-general/2582-how-to-play-coop-multiplayer-maps-in-single-player?start=18
(Def section+Obj section+6=File size).
If the rubbish is already in the end of file, this program cannot recognize it... yet... for now still have to delete it by HexEditor.