Adding open captions at current playhead position

I am creating open captions in a rather long (2hr45min) movie for my EFL students. Whenever I add a caption using the + icon in the caption panel, the new caption "in" timestamp defaults to the "out" timestamp of the previous caption. Since there are many periods of silence between spoken lines in this movie, I'd rather that the new caption "in" defaults to the timestamp of the playhead. In other words, as I play the video, I stop the playback just before the character speaks, and then click "+". But then I have to copy the current timestamp and paste it into the "in" for the caption. Then I have to go back and play the video to the end of that line, pause, copy the timestamp, and paste it into the "out" for the caption. That becomes quite cumbersome for such a long movie. (It's taken me 2 hours to caption 15 minutes.) Is there any way of making this process more efficient?

Thanks in advance for any help you can offer!