With this tool (or script) you can correct your timecodes for the value than you need.
I.e., you have the next list:
00:00:00 Waiting streamer
00:01:58 Stream has started
00:32:45 Main theme
01:41:12 Next topic
And corrected value for each line, i.e., 00:01:58.
Now you can take corrected list on second board (recalculation takes automatically).
Demo page: https://sutangu.github.io/timecode-correcter