This is what I was referring to. The data only includes 14 of the 21 total OTE games they played between regular season and playoffs. It doesn't include any of the playoff games.
At the time, Amen was 16/40 (40%) on halfcourt layup attempts and 27/52 (51.9%) on overall halfcourt rim finishing with 11 dunks in the halfcourt, but had 31 transition dunks and was at nearly 90% (53/59) on overall transition rim finishing, which boosted his overall rim finishing to 72.1%.
Ausar was 6/23 (26.1%) on halfcourt layups and 11/28 (39.3%) on halfcourt rim finishing and only had 5 halfcourt dunks. He had 21 transition dunks and was 42/56 (75%) in transition rim finishing, which boosted his overall rim finishing to 63.1%.
Black was at 27/52 (51.9%) on halfcourt layups and 31/57 (54.4%) on overall halfcourt rim finishing with 4 halfcourt dunks. He had 10 transition dunks and was 19/27 (70.4%) transition rim finishing, which put his overall rim finishing at 59.5%. His sample size was 22 games vs 14 for the twins. 
According to the Box and Ones scouting report, Amen finished the season at 50% on halfcourt layups and 59.2% on halfcourt rim finishing in 21 games, which is an improvement and not bad in general, but still pretty similar to where Black was after 22 games and not really good given that Amen is 20 already, playing down in age and competition level, and is a super freak athlete.
Ausar finished the season at 40.5% for halfcourt layups and 51.1% at halfcourt rim finishing.
I'm not sure what Blacks updated halfcourt finishing numbers look like, but his overall 2pt% was 50.7% at the time the first sample was posted and he finished at 51.3% for the season, so it seems like his numbers might have been fairly stable.
full season halfcourt numbers for the twins.
Outside of the paint both twins halfcourt jump shooting and overall halfcourt fg% were bad and didn't improve much in the final numbers.
Twins earlier half court efficiency sample
Amen was at 28.8% for jump shots, 24.3% on catch & shoot, 33.3% on dribble jumpers, and 39.6% on all halfcourt field goal attempts. He finished the season at 28.7% on jump shots, 27.8% on c&s, 29.6% on dribble jumpers, and 40.4% on all halfcourt field goal attempts. 
Ausar was at 30.7% on jump shots, 28.2% on catch & shoot, 33.3% on dribble jumpers, and 34.4% on all halfcourt field goals. He finished the season at 31.6% on jump shots, 32.5% c&s, 30.4% on dribble jumpers, and 36.7% on all halfcourt attempts.
The Thompson twins both saw big declines in their 2pt% in the playoff games that werent included in the earlier sample (66% to 52% for Amen and 56% to 50% for Ausar), despite their overall halfcourt numbers going up, which seems like it suggests that they were probably getting significantly fewer transition opportunities in the playoffs. They did seem to improve their halfcourt numbers inside the arc in the playoffs and Ausar's overall 3pt% went up quite a bit, so thats something, but the overall season sample still makes it seem like they feasted in transition against overmatched OTE opponents, but mostly were bad when they had to play halfcourt basketball.
The twins deserve credit for potentially being outlier transition threats, which makes sense with their athleticism, but they simply aren't going to be able to play nearly as high a ratio of transition vs halfcourt possessions when they play at levels higher than OTE. They'll have more spacing in the halfcourt in the NBA, but they don't currently compare all that well in the halfcourt to many NCAA prospects that are dealing with similar spacing issues and playing against better competition.