If you need a separate account for your business, Google have this to say (from the same link, above):

In this case, you may submit a new application. Please make sure that the account type (individual or business) and payee name are different from your original application, and ensure that you can accept payments to that payee.

For each company with an account, you need to make the payee the name of the company and create bank accounts for that company (which you will be doing anyway).

I've had some success with Adsense. OK, it took me years to build my Adsense revenue to that point, but when that point came it made sense to incorporate a company to handle the income that my sites generate. Of course, after setting the company up I needed to create an Adsense account in the company's name. Hence the question.

The company is doing really well.

But get this. After I set the company up and created the Adsense account for it, I started transferring my most lucrative sites to the company account first. I've currently got 3 high earners there. I've just received an email from Google inviting me to particpate in a 4 week programme for "high potential accounts"! I suspect that the programme won't teach me anything I don't already know (such modesty!), but there's always a chance.

This just demonstrates that Google do keep a watchful eye on performance. Scary huh?

On the subject of multiple Adsense accounts, you might find this informative post on Pro Blogger illuminating. The Pro Blogger reader whose experience is described moved their high performing and low performing sites into different Adsense accounts. The revenue on the high performing account went up whilst that on the low performing one went down. This ties in with the smart pricing affects whole accounts not sites theory. I don't know how good the testing was, but that post is certainly food for thought.

My experience with using multiple Adsense accounts differs from that of the Pro Blogger reader in one important respect. The revenue from both accounts has gone up!

After a year or so, I'll create an ultra Adsense account and move the highest performing sites owned by my company to the new account - see how smart pricing affects that!