Based on this, I'm trying to figure out the data for some other moves using Gord v Gord in training mode. Here's what I've got so far, keep in mind this might be off a little bit.
623A is -6.
After normal blocking 623A, 2A gets blocked, but microdash 5A connects. Because the buffer for dashes is pretty big, I'm confident that a reversal microdash normal has no extra startup time from the dash itself.
After shielding (green shield first hit), 5B hits.
Still trying to figure out the startup on it for use as a punish.
623B hits on frame 10.
I had to go outside of Gord vs Gord for this one and use Hyde as a training dummy instead. Hyde's 66C is -6 normally, shielded -9. B-Reaper gets blocked after shielding. On the other hand, Hyde's 5B is -7/-10. Reversal B-Reaper punishes shielded Hyde 5B.
623C hits on frame 7.
Since 2B is -4 on block, shielding it makes it -7. EX-Reaper is fast enough to punish shielded 2B but not fast enough to punish shielded A-Reaper.