We heard rumbles of this last night, but this morning The Verge has it cold: AdAge’s story that AT&T planned to spend up to $150 million launching the nascent Lumia 900 is incorrect. Instead, it notes, the sum will be essentially a normal figure for a high-level smartphone debut. Our post was therefore mistaken.

Of course, this snaps AdAge’s thesis that AT&T is working to position the Lumia 900 as insurance, of a sort, from being to dependent on the iPhone, a handset that it has lost exclusivity with. AT&T instead appears to be gearing up for a standard, if large, launch.

What happened? I have a guess. It’s my suspicion that the ‘up to $150 million’ figure is the total ad budget for the Lumia 900 in the United States, including monies from both Nokia and Microsoft for promotions, in-store accouterments, sales incentives, TV ads, and the like.

That’s much more reasonable. It’s still a ludicrous sum of money, but it makes much more sense from a combined-input perspective. Or, it could be, the original source was simply flat wrong. That happens. But publications such as AdAge don’t make mistakes like this often, so it’s for all of us to keep digging.

Keep in mind how important the Lumia 900 is for both Microsoft and Nokia. Some astronomical sum is being spent, and I want to know what it is.