US Supplies of 2010 Toyota Prius Limited By Japanese Demand?

Received from "All About Prius" today:
With US buyers eagerly awaiting the first shipment of 2010 Toyota Prius models, now on the high seas and appearing at dealers late this month or early in June, Japanese demand could squeeze availability of the new hybridhatchback.
Toyota has already received orders in Japan for 80,000 of the new Priuses, or 80 percent of its total projected annual sales in that country. Japanese buyers now wait an average of four months to take delivery of their 2010 Toyota Prius.
According to Automotive News, Yoshimasa Ishii, Toyota's managing officer in charge of overseas marketing, said the company might have to reallocate production now slated for North America to meet domestic demand.
In January, Toyota said it planned to sell 180,000 new Priuses in the US during the first 12 months the car was on sale. Now, the company is saying it plans to sell "roughly half" its production of 300,000 to 400,000 in the US before January 1st.
The company faces two constraints: Ramping up production rates to its full capacity of half a million units without affecting build quality, and a limited supply of the nickel-metal hydride battery packs shared by all Toyota hybrid models.
Packs are now limited to 500,000 per year, but that number will rise to 800,000 next year, putting Toytoa on its way to meeting the goal of 1 million hybrids a year by 2012.