It does suck. You are correct, but you have only been waiting for your 485 application to be processed for just over 1 year (your RD is 1/12/2007 if I recall correctly).
Your post seems like a bit of deja vu... (
http://boards.immigrationportal.com/showthread.php?p=1688714#post1688714)
Do a search on USCIS.gov to see how the RD is used for applications. You'll find they always use the RD for processing applications and even try to provide processing dates by RD.
For I485 cases, the PD is used to identify who is eligible for a visa #. This then should provide USCIS with list of cases that can be processed to completion in FIFO order.
If PD was used to identify the order in which cases get looked at and processed then I'd be at the front of the queue along with folks like Akbari. However I've been waiting for 18 months (or so) and am behind others who filed in 2003, 2004 and 2005.
Ask your local congress person's immigration aide. They'll tell you the same "story".