It’s a great question actually, and the answer has mostly to do with Romanization. Japanese and English are sufficiently structurally different, that even the sentence length won’t necessarily be one to one (eg subject and object inverted).

Another thing that happens is time code shifts that come from differences in frame rate between source material and what the subtitlers end up with (eg 24 vs 23.98 if I’m remembering correctly), which can cause subs to have what we called “ramping” issues over time (timing gets less and less accurate). So you have to go through and reset all the lines anyway.

That being said, we DID do this sometimes, but maybe that takes your time down to 25 minutes, the hard minimum possible time to accurately subtitle a 25 minute show.

And translators hated having to add the times codes (or copy paste their translations over the CCs) — they preferred to just give a script to the subtitler and let them handle it. And actually, if it’s a really good subtitler, they can! In about 35 mins.

So I think the translators were probably right to push back, as it’s only 10 minute savings for probably >10 mins on their part.