PS3 Fat Refurbished vs Recertifed ; What did Sony really do for me?

[WHS]

My FFXIV PS3 Box: Since that is the only thing I use it for and would like to know

I just sent in my launch model ps3 60gb to Sony for repairs. This is the 2nd time since I bought mine back when ps3 was first launched. First time was loud fan noise and this time the system booted with video post. Sony said it had to be repaired and charged me 140 bucks to repair it.

Today I call up because the e ticket says that my baby is on its way back to me and that was a fast turn around. Less than a week overall. Sony rep says they are sending me a recertified model instead of fixing mine.

I've heard of refurbished before but what is recertified?

I am also curious if they check thermal paste and make sure its properly applied to the replacement model. I have had to do that once on ps3 and it is no joy to do. PC on other had is relavtively easier to do by a long shot.

So my questions are:

Did they really check everything out before sending me that replacement model?

What is the difference between Refurbished by Sony and Recertified by Sony?

Do they really test each voltage point with a probe and make sure that thermal paste is really on right?

Do they stress test the system or just see that it boots and call that good?

Why was I told they had to fix mine and then they turn around and send me a different one instead? I was told replacement weren't available.

I did find a gamespot article that a similar set of questions someone else was asking but did not see my specific questions answered.

If anyone else has had experience with sony and ps3 replacements that would be a big help too me as well.