How do solar companies calculate the manufacturing cost per watt?

Recently, First Solar claimed to have broken the $1/watt barrier, saying that they have achieved the lowest manufacturing cost in the industry, $ 0.98/watt. Is there a standard way of calculating this cost across all solar companies or it varies?

To put it politely, accounting voodoo. I'd wager they would count the costs minus whatever rebates that are given for consumers and call that the consumer price. If this is done in Germany, who have the highest level of rebates in the world for solar panels (err, Germany or Japan, I'm not exactly sure) then that number might really be something like $2 a watt or something.

I'm earnestly hoping that they are publishing this without government rebates, but a small dose of skepticism is generally healthy for an investor.
To be sure, First Solar isn't talking about total price as installed, they are discussing the price of manufacturing. The question is whether or not they are including rebates in their price of manufacture, for it wouldn't be the first time a company has been misleading.

Also, 1 dollar per watt of silicon? Whose estimates are you running off of Mr. Fortuna? I know the story of the Si price drop, but I didn't think that it was that much.

Just because you are responsible makes no guarantee that all people are responsible. Additionally, I am doubly suspicious of any company that uses tellurium in their product, which is more rare than platinum, and I do think it out of line to offer a healthy dose of skepticism in their press releases, especially when they have a disclaimer on the press release. Heaven's fore fend there is a raw material crunch right when the whole game starts to take off. The specific "trick" I am fearing is taking the federal rebate that Germany offers for things like investing in solar plants, up to 50% or so if you do it right.