The shadows look bad at any zoom level whereas the preview in ACR 10 looked good at any zoom level.
There was a LuLa forum poster in a discussion years back I wished I'ld saved to pdf that posted screenshots showing varying black point density appearances on calibrated and profiled displays rendered through color managed apps including Apple's Preview, web browsers, Adobe apps and another Raw converter. It was surprising to see the differences.
Now that you've stated that your shadow transitions on EDITED ACR Raw previews is the version you prefer but not what appears in Photoshop, I'ld suggest you rule out the camera by shooting the same dark suit subject with a different model of camera.
Just speculating but not all camera's Raw data is interpreted and rendered the same between different camera models when assessing color managed previews in Raw converters. It may be ACR is being told by the demosiacing algorithms where black is and getting you to perform edits that aren't previewing through normal color managed transforms in the generation of black points and shadow ramp up appearances.
This is not normal and quite rare what you're experiencing so I'm at a loss on how to resolve your issue. I don't have this problem and it appears from the lack of responses no one else is as well.
Good luck sorting this out.