E228WFPc Jan 2007 vs E228WFPc July 2008

I recently purchased a new E228WFPc to add a second monitor to my Vista Running computer.  Once installed I was struck be by the difference in brightness between my first model bought last year and my new monitor.  I have included a picture below.  I tried to increase the brightness and contrast on both as well as the colors after Factory Resetting each and both still are signifigantly off in brightness. They are both being run off the same video card, both via DVI from a NVIDIA GeForce9600 G.  I tried swaping out the monitor card ports to see if was my card with the same results.

I'm wondering:

a) do Dell LCD monitors get darker over time?

b) was there a brightness upgrade with the later models even with the same specs

Here is an example with Google.com open in both to show the difference in white balance:

Thanks for your input.

Brad