@uanime5: vol 4 and 5 actually
were translated and released by Ironcat, too, but only in floppy, single-issue comic book format. (Source:
https://www.comics.org/series/21727/ )
All 5 volumes came out gradually in this format between 1998 and 2001.
Starting in 2000, collected volumes started to be released in book form (like most manga is) starting with vol 1. However, Ironcat didn't get a chance to release vol 4 and 5 of the series in this format because the company went under in 2003 (shortly after vol 3 came out in January 2003).
I have all of the floppy issues of the series, but not only are they in left-to-right format, but the quality of the translation is pretty middling. On top of that, some panels are flipped while others are not, speech bubbles occasionally have re-drawn stems to preserve speaking order, SFX have been re-drawn on top of the Japanese SFX to make English words, not to mention the print quality, which is inconsistent (sometimes being blurry).
Ironcat basically just butchered the series, as they did with a lot of their releases. Which is why I decided to re-do the series on Japanese raws. I began work on the project many months ago and planned to release full volumes at a time, but I put it on hold, focusing on other projects. However, when I randomly saw the first chapter of volume 4 released, I decided to start releasing my re-done chapters from the start.