Ecomomics of the Chrome netbook: I don't get it

I'm trying to make financial sense out of Google's Chrome notebook lease plan. As I understand it, rather than sell the hardware, schools would lease these little devices for $20 a month with a three year commitment. The school does not own the notebooks at the end of the plan.
Since I don't have enough fingers to do the math, let me grab a calculator. If we were to do a 1:1 project in our district for grades 3-12 we'd need about 6000 units. 6000 X $20 X 36 months = $4,320,000 or $1,440,000 per year. (About $300,000 a year more than our entire current tech budget.)
While the Chrome notebooks look like nice little devices that are easily managed, have fast start-ups, and promise good battery life, they also are limited in functionality - no Flash, limited offline functionality, and few available apps. Big time wireless network upgrades would be needed and machines that could be used for mandated online testing would still need to be maintained.
Let's run another set of numbers. Supply each student with a $350 Windows netbook. Just for fun, we'll throw on the DeepFreeze management system. 6000 X $350 = $2,100,000. If rolled out over three years: $700,000 a year. About half the cost of the Chrome Netbook. Add OpenOffice for off-line productivity and stay with GoogleApps for Education. Runs Flash and might play well with state tests.
What am I missing here? Why would I want to pay twice the money for half the functionality? And be stuck in a budget with tails (risky in times of volatile school funding). Is the Google lease plan just for districts that qualify for E-rate funding for hardware?
I love you Google for your GoogleApps for Education, but you may need to re-think this plan.