Another thing to keep in mind is that it isn't necessarily 200k US deliveries, but 200k deliveries where the tax credit was claimed.
I do not think that is correct. No one claims the credit till they file taxes, so that would make the system practically unusable.
IRS allows manufacturer to certify what cars get the credit and what the credit level is. IRS also uses sold vs acquired, but at least acquired is based on State title transfer.
Internal Revenue Bulletin: 2009-48 | Internal Revenue Service
Possible June 30 bonus day (from @luvb2b or others):This notice also provides guidance to taxpayers who purchase motor vehicles regarding the conditions under which they may rely on the vehicle manufacturer’s (or, in the case of a foreign vehicle manufacturer, its domestic distributor’s) certification in determining whether a credit is allowable with respect to the vehicle and the amount of the credit. The Service and the Treasury Department expect that the regulations will incorporate the rules set forth in this notice.
All references to § 30D in subsequent sections of this notice are to the provision as amended by the Act. Guidance regarding the credit under § 30D for qualified plug-in electric drive motor vehicles acquired before January 1, 2010, is provided in Notice 2009-54, 2009-26 I.R.B. 1124. This notice also amplifies Notice 2009-54 and Notice 2009-58, 2009-30 I.R.B. 163 (relating to the plug-in electric vehicle credit under § 30) to provide that a vehicle is considered “acquired” when title to that vehicle passes under state law.
The new qualified plug-in electric drive motor vehicle credit phases out for a manufacturer’s vehicles over the one-year period beginning with the second calendar quarter after the calendar quarter in which at least 200,000 qualifying vehicles manufactured by that manufacturer have been sold for use in the United States (determined on a cumulative basis for sales after December 31, 2009) (“phase-out period”).