It is a S.M.A.R.T. attribute, which is only useful for technicians.
Yes I know but such information sometimes becomes very important to the end user and many people use it to determine whether their hardware works properly.
I am not a fan of such frequent diagnostics

- but when I buy new hardware I always check it. It's an SSD in this case and this is extremely important for me. I don't care of my notebook as much as I care of the data stored on the disk. For a couple of years I use only a notebook and I don't want another PC's at home, at work. Just one computer for everything and everywhere. So there is a lot of very important data for me - home, family and business. Of course I back it up frequently but not everyday - it's not a server! But I don't want the data to become corrupted or lost a week of work.
Nevertheless I've made my first check - I put SSD from bay A to bay B and vice versa.
Huh.... POR Recovery Count stopped.... I have made several shutdowns and it works like a charm... Shutdowns are counted - but properly, without any unnecessary interrupts shown in SMART. Power-on Count is now 35 and POR Recovery Count stopped at 28. Before Power-on Count was always 1 ahead of POR.
That may seem to resolve the problem but I will check other options e.g. putting the 840Evo into another notebook.
Apart from that I suspect I put the disks into wrong bays. I am not sure at this moment because I have to open the cover once again and check it but it may be related to the fact that the first SSD with OS should be mounted in the first bay, and the second (storage) in the secondary bay.
Long time ago it was important with ATA drives .... I even didn't think of it nowadays with "SATA-AHCI-GPT-SSD" damn super modern disks!
It looks like I should refresh some knowledge from good old times ...
(edit)
Well it's funny but the OS disk (Samsung 830) is in the secondary bay and the "data" disk (Samsung 840Evo) is in the first primary bay - and this is the configuration which doesn't provide errors on the 840Evo.
I will stick with it for a while and check if that's OK. If there's no more POR Recovery Count errors for the 840Evo I will retain the configuration and assume it as a solution to my problem.
I don't know how to help other users - if you have 2 disk bays, try the other one. If not - maybe it's a BIOS function... some kind of energy saving stuff. I have 1 or 2 settings related to energy saving but I didn't touch it. And finally comes the Win8 OS - maybe there is a bug which causes such SSD behavior but I doubt it because as some users wrote before - it happens also on MacOS.
And maybe it's a bug inside Samsung firmware which will be repaired in future firmware versions.
Anyway swapping the SSD disks helped in my configuration so I keep it working.
Sometimes I envy you Mac users that you don't have such problems arising around M$ systems

. I am a big fan of iOS devices and I don't realize living without iPhone and iPad - but I've been using M$ PCs for decades and I am unable to leave this platform for Apple. That's a pity but life goes on...