Just so that we still stick to facts rather than anecdotes, anyone who is interested in the actual facts and truth of CFD pricing is recommended to read the following (or similar) papers:
http://kevindavis.com.au/secondpages/workinprogress/CFDs-final-Nov29-09_2.pdf
Particularly the following passage on page 20 and following applies:
"4.3.1 CFD spreads and the spreads on the underlying Because DPMs are rebated the OIC and face very low trading costs, the zero profit spread from market making activities resulting from competition should, in the absence of hedging risks, be not much wider than those in the underlying market. However, for customers, there is a potentially much wider spread which is consistent with them being willing to take positions in the CFD rather than in the underlying using margin loans, short selling, or trading the physical. This arises because the effective interest cost on long CFD positions is lower than that associated with margin loan purchases and the interest return is higher than on investing proceeds from short positions in the physical. Incorporating the Open Interest Charge on positions levied by the ASX of 1.50% p.a., the effective interest cost (return) on CFD positions is r +0.015 or r -0.015 p.a., where r is the RBA target cash rate. Over the period of our study, the indicator margin lending rate averaged 3.4% higher than the RBA cash rate. The interest paid on bank cash management accounts (in excess of $50,000), which would be an upper bound on returns paid by brokers to retail clients on cash generated from short sales, was 1.1% lower than the RBA cash rate."
--> Essentially the point is that CFDs are priced completely differently than their underlyings. The reasons for that are interest charges, different commission models and generally wider spreads than the underlying. Just because some DMA Brokers show identical prices and spreads between CFD and underlying cash equity means nothing (well, nothing other than that the CFD price and spread shown is actually showing the price and spread of the underlying), because the ensuing cash flows are entirely different. All it means to have identical prices shown at the outset is that the underlying economics are mimicked by the CFD. But still that does not lead to an identical pricing during the life time of the CFD by any means.