Question how to expand timing of sub/idx subtitle

[jimdays2788]

I know that I can use Subtitle Workshop to expand (lengthen subtitle duration) of srt subtitles (see screenshot). However, I want to expand (not delay) sub/idx subtitles, and Subtitle Workshop won't allow me to input sub/idx.
Subtitle Creator only allows me to delay sub/idx subtitles.
My question is: What software can be used to expand sub/idx subtitle timing?

[hubblec4]

with this powerful tool you can do this.

http://forum.doom9.org/showthread.php?t=145277

[jimdays2788]

Could you post a screenshot of how to extend (lengthen duration, not delay) all sub/idx subtitles in a movie? I could not find a method to do this when I looked at your software, or the documentation. For example, I would like to extend (lengthen duration) all subtitles in a movie by 0.3 second (and also automatically prevent overlapping, since if some subtitles were extended, they would overlap with the next subtitle. In this case, those subtitles should only extend to the next subtitle.
Subtitle Workshop can easily do this with just a mouse click (edit>timings>time expander), but only on srt subtitles. I want to lengthen duration on all sub/idx subtitles in a movie.