I don't know why I'm not happy from getting dhl email, i really doubt to get money back with mercury 

So, talk performance.  How are they?  Not posted perf, but actual.

Most seem to work pretty well, but some are getting lemons...

a few hours ago:

https://bt.irlbtc.com/view/170332.msg3385915#msg3385915

sorry can't resist

I sometimes wonder if when one first fires up a new miner and there's bad cores and high temperature, if it's better to let it run just like that for a couple of days.  The rationale would be that if in shipment some ball grid away  points cracked and separated but still making marginal electrical contact, there will be a higher resistance point there that will be hot, hence the high temperatures.  It might get hot enough at that point or points to liquify the solder while nearby healthy solder points remain okay.  Then after turning it off and cooling, when you restart that point has a solid solder contact.

Mine has been running at 100% on all 4 cores overnight and maxed out at 137.5GH/s avg so I would expect max avg of a Saturn to be 275GH/s and Jupiter 550GH/s, 5 second averages not withstanding.

your WU is very good. I've 7475 for my jup.

Merc arrived, 10 mins unpacking and checking (using the various lists posted here so I didn't forget anything ..BIG THANKS FOR THAT)
Well packed and undamaged. They learned. Oh, no ethernet cable if you don't have a spare.

Everything whirring away...no stats in the KNC page...not hashing.

2nd screen with pool details didn't have cgminer enabled, did that restarted cgminer and we're off. Firmware .96 on it when it arrived.

Now been running about 10 mins at 110 to 139 Gh and 39 C with no extra cooling.
Feeling confident ish

Cat in box. He says it's a quality box and he knows these things

All I want is to break even...if that is even a small possibility now or not. I paid $4k for my Saturn. If things are static and stay the same it will take me 60 days or so to break even, I can deal with that. But so many more hashing power coming out its just gonna kill me/us. What to do. Would it even be wise to upgrade my Saturn to a Jupiter? If I do that, I'll be in the same boat, having spent more money. Yea, a little more hashing power but more cash out of my pocket. Oh, what to do.

WU is just a ratio of accepted shares to rejected shares.  It depends only on your hash rate and (effectively) how many difficulty 1 shares you submit that get accepted.  Difficulty is not part of the calculation, and doesn't affect any of the factors that are.

Are you saying that your WU changes when difficulty changes?  It sounds like you are saying that your WU varies over time even with no difficulty change, so I don't understand where you are deriving the relationship to difficulty.  Diff only changes once ever 2016 blocks.