Last BIOS time on Task Manager
Very interesting question indeed! I spent quite some time looking around, and here's what I found so far:
It's not just you (that's one of the earliest references I found to this feature, pre-dating the GA release of Windows 8 by a couple of months).
It's possible that Condusiv Technologies/Diskeeper Corporation's ExpressCache software is responsible for this, but I'm not sure. From what I can see it's not confined to Samsung laptops, although all other references were to PCs with SSDs, so those may have had ExpressCache installed as well.
Perhaps you can see whether NirSoft's InjectedDLL detects anything on your system, since I don't know of any other way for a 3rd party to accomplish a Task Manager modification like this besides DLL injection.
There's precious little information about this, and no official Microsoft documentation as far as I can see (not surprising if it's not an OS feature). I guess that explains why you received no replies when you enquired about this previously here.
The best source of information I've found so far is this TechNet thread, where someone says that "Last BIOS Time" is an indicator that only shows up under some conditions, and someone else says that it displays the time taken to boot up after the PC passes the BIOS screen.
Unfortunately, no insight into what precisely those conditions might be, or indeed whether it's even an in-built OS feature at all.
Just in case anyone stumbles on this question, this is indeed a built-in part of Task Manager. The string is in Taskmgr.exe.mui and can be seen with the following PowerShell command:
select-string 'last bios time' C:\Windows\System32\en-US\Taskmgr.exe.mui -enc unicode | select matches
Although I'm not sure why you are getting it displayed as 0.0 seconds, the purpose of the "Last BIOS time" is to tell you how long it took to load the BIOS, it is the amount of time between pressing the power button, and seeing the screen that indicates that windows is loading.