Weight-based shipping translation not updating

I'm using the weight-based shipping extension and my site is translated into Japanese. The translation for what it is called is not exactly what I wanted to use so I found the specific text in one file: /admin/language/japanese/shipping/weight.php. I modified it to what I wanted but when I check out it still displays the old text. I've searched though all of the Japanese translation files and can't find any instances of the old text.

1. Is the japanese weight.php file the correct one to edit or is there some other file I need to edit?
2. I tried uninsalling and reinstalling the extension but that didn't help.
3. In the past I've occasionally encountered server-side caching issues but those have always cleared up on their own within a few hours. This has been 2 days.

Anyone have suggestions?

/admin/ language files are for the admin side. You'd want to edit the language files in the /catalog/ directory. The specific file you're looking for is:

/catalog/language/japanese/shipping/weight.php

Thanks.