https://www.mlb.com/news/braves-2020-draft
After spending the fall making his hip turn slightly more aggressive, Shuster saw his fastball velocity rise from 89-93 mph to 91-95 mph. He touched 97 mph a few times and continued to show good swing-and-miss stuff with his changeup. His slider remains questionable, but it has shown some improvement.
https://www.baseballamerica.com/stories/jared-shuster-could-just-be-scratching-surface/
In four starts this season, the 6-foot-3, 210-pound lefthander's velocity had bumped from the upper 80s to the 91-95 mph range thanks to a revamped delivery. He posted a 43-to-4 strikeout-to-walk ratio in 26.1 innings before the pandemic ended the season.
I don't think he's thrown that hard. They've used him in short stints and his velo has mostly been reported 90-92. That is a big difference from 95
You're using the high end to compare things to - that's nuts. He only has to hit those numbers ONCE for them to say he can get there. That's a range, and the vast majority of his pitches fall well below the top end of that range.
Your BA quote mirrors my point exactly - a delivery tweak led to a couple more MPH. A huge number of those fastballs would have been 92 or 93 MPH for that to be his established range. That might have been a "big fastball" in the 1980s, but certainly not since. A couple MPH doesn't exactly represent a "spike". Did the range go up? Sure. That came from a tweak, not because they suddenly expected that number to keep climbing from there. There's probably another MPH in there if they can further refine his delivery, but nobody's going to confuse him with Ynoa.