After updating to macOS High Sierra 10.13.1, when I erase files, I don't get back the space

I found the solution, someone else posted on Apple Community forum and Macrumors forum and it worked for me and I got back all my free space :

"I eventually use this command to find all the local timemachine snapshot

tmutil listlocalsnapshots /

And then delete them one by one using

tmutil deletelocalsnapshots <snapshot_date>

This 'feature' with APFS + TimeMachine local snapshot is very annoying as time machine will cache whatever you dump into your computer locally on your machine. If you dump 300GB files on your desktop, it WILL cache it in the local snapshot. And it will stay on your computer even after you delete the original file. Yes, you just lost 300GB space even you have already delete the original file.

You will have to manually delete the local snapshot in TimeMachine to get back your space."

I was checking About This Mac>Storage and then Disk Utility,

In Disk Utility the Free space was way way different than Available space, like 34GB Difference and the difference was purgeable.