Consistent Backgrounds

I'm wondering how JCrew gets their backgrounds so consistent.
Check this out: https://www.jcrew.com/p/womens_feature/newarrivals/justin/cableknit-swea...

If any of you shoot eComm you'll know if you move even an inch from the background you'll get changes in the background brightness. I know the exact lighting setup that they use and also know that the photographer moves around quite a bit while shooting so this must be a trick done in post.

See, almost every shot they take has the same background color/brightness: https://www.jcrew.com/c/womens_feature/newarrivals
This has to be done in post.

I know how I'd do it, but what I want to know is how they do it. The results I'm getting aren't as good. I recently shot a massive eComm shoot and my backgrounds are already pretty darn close out of camera, but I want the consistency to be on par with what JCrew is doing. Any tips or tricks for doing this in post quickly and efficiently would be greatly appreciated.

Thanks!