Ok, this might be due to Powerstrip not supporting your card. You have a HD 6xxx card. As far as I know, support is only documented up to HD 5xxx:
http://forums.entechtaiwan.com/index.php?topic=2036.0I thought Powerstrip might be targeting the wrong output, but in your logs you can clearly see how it takes the 1600x1200 timings, so it's doing it right, it seems.
Just to be 100% sure, I'd test this with only the target monitor attached, and using it as the primary (desktop) monitor. By the way, are you using digital or analog outputs? I'd test this with a VGA cable in case your trying with DVI.
When working with Powerstrip, maka sure you have the key shortcuts enabled. In particular, make sure CTRL + ALT + S is working. This is used to restore the default safe settings, in case you mess things up. I need to use this from time to time when doing tests.