Snatching and recovery points.

OK so I know that looping the snatch over the towball is bad and a big no-no. I've also noticed that a lot of fourby's have a recovery point that they can slide into the provision for their towball tongue. I've also noticed that my shackles are rated at 4.7t "SWL" (I'm assuming this is 4700kg??)

My question is this:-
If my snatch strap is rated at 8000kg and my towball at 3000kg then mathematics tells me this is a bad idea, but to hook the snatch onto a proper tow point with a shackle rated at only 4700kgs still leaving me a defecit on the snatch's rating of 3300kgs doesn't make feel a whole lot safer! Unless the "SWL" stamped on the shackle is some sort of different measurement???

I've also seen recovery gear rated at a "massive" 10,000lbs!!! Which is approx 4500kgs? Am I right? Is this just a marketing gimmick and a trap for young players?

Anyone that can explain all this mess in idiots terms would be appreciated! I'm one of those people that need to understand how it works before I'll do it! :-)

Cheers
Scoey!