Discrepancy between reported VM HDD size and actual size on disk

I very recently upgraded my host iMac, restored PD13, transferred the license, and transferred my PD13 Windows 10 VM .pvm file.
My previous iMac system was version 8.1. I am now at 18.3.
The new host uses a SSD for the HDD.
PD13 and the VM both run fine as expected on the new host.
My VM HDD is variable in size up to 512GB.
I have noticed a discrepancy between what PD13 says is the size of the VM HDD and the physical size of the VM file on disk.
I reclaimed disk space and the size of the VM HDD displayed in Settings is 364.2GB. The physical size of the VM on disk in Finder is 391.1GB.
Why is there a difference of almost 27GB?
I DO NOT back up this VM on Time Machine. I back it up manually.
I DO NOT use Snapshot.
Any ideas or advice how I can get that 27GB back would be appreciated.

 

Hi Robert. This is because the file size calculation differs for Mac and Windows. Please refer this article for more information.