Did not ask as I'm not doing commercial. Probably if you are doing that,you may need something to cover other aspects of liability like property damage and medical in case of a catastrophic failure. I would not want to get someone hurt and have to cover those costs out of pocket.
This is a very old thread (over a year) and at no point has anybody mentioned what their location of operation will be. ie what country.
Nor does 1 million give any idea of level of cover without a currency against it!