Guess it's my fault after all, because that worked when I edited the CSV via Notepad++ but not OpenOffice.
The trick I'm doing to fix the CSV formatting issues for metasmok.csv and smokes.csv apparently isn't working on explos.csv very well, causing the game to think it's broken and thus it uses the default settings. Guess I'm going to have to sort out a new trick.
Time to mess with the explosions