The drop was smaller than what iSuppli had expected going into its analysis of the Verizon iPhone, said Andrew Rassweiler, the senior director of the El Segundo, Calif. company and the manager of its teardown group.

"If you were to do an apples to apples comparison, no pun intended, [the Verizon iPhone 4] is not that different in cost than the AT&T iPhone is now. It's only a few dollars lower, somewhere around $5 lower."

Rassweiler's estimate differed from one cited in earlier reports about the cost difference between the two phone models. In a , iSuppli compared the Verizon iPhone's "bill of materials," or BOM -- a list of component cost estimates -- with the BOM it assembled last June after the iPhone 4 debuted on AT&T.

According to that press release, materials and parts for the new CDMA 16GB iPhone 4 run $171.35, 8.7% less than the $187.71 estimate the company put on last summer's model. Most news outlets seized on the press release's figures, and calculated that the Verizon iPhone was almost 9% cheaper for Apple.

But last year's number for the AT&T iPhone is outdated, Rassweiler acknowledged, which is why a more accurate comparison is to a new estimate for the AT&T iPhone 4 that iSuppli completed just last month for a client who wanted to know Apple's then-current costs.