High third year RSI social charges?

My wife runs a small business making and selling costume jewellery. We have a Siret number and the business is registered as Benefices non commerciaux - Regime special (ou micro BNC). She has paid cotisations to RSI since the start of the business in 2008 as follows:

• 2008 net income 395 euros - cotisations 757 euros
• 2009 net income 3,554 euros - cotisations 1,996 euros
• 2010 net income 10,912 euros - cotisations 5,350 euros

The net income is the amount after the deduction of the 34% allowance. I understand that there is a minimum amount to pay for the first two years but the third year seems rather excessive. We have been told by RSI to expect to pay a similar amount in 2011 if the net income remains the same. Can you tell me if these figures correct please? If so it hardly seems worth running a business if you have to pay half of your net income in social charges.

My wife has now applied to join the auto-entrepreneur scheme as this should reduce her social charges. I am assuming that she will come under Activites liberales relevant de la CIPAV (BNC) and will pay 18.3% social charges. Could you please let me know if this is correct?