Your information doesn't match up. How does $400 = $1200?
You are correct.
If you will notice, dell dropped the price on the 1730 on Monday (yesterday). This may explain why their pricing was so screwed up. If you visit the site now you will see that they are boasting the new lowered prices on the 1730.
So had I bought this system say two weeks ago, I would have paid 2,700, had this sale been legitimate it would have been 1,480, if I bought the system today it would be 1,949