Yeah, my process goes roughly like this:
1) You start with a subtitle in any state, in any format, made by any software.
2) BDSup2Sub converts the subtitle into a collection of DVD-sized PNGs and an XML file. This collection is cropped.
3) The Perl script converts this collection into another collection of uncropped DVD-sized PNGs and an XML file.
4) You can then use BDSup2Sub with the /acrop:0 flag to convert this second collection back into a DVD subtitle. And it's uncropped!