Rev. 72 - Only m2.4xlarge?

I just read about the new Rev. 72 available on AWS.

Currently I am running Rev. 70 on m2.2xlarge any yesterday I bought a reserved Instance (light utilization) to lower the hourly fees.

Now there is Rev. 72 but it only seems to support m2.4xlarge? Or is there a way to downgrade later?

Does this mean I just spent >$1000 for nothing?

As far as I have seen, upgrades to larger instance types is not possible for type SuSE-Linux...

Kind Regards,

Fabian