I wonder how many of the supporters of this policy change it is only right that the SE pay the same as employees, and besides most SE fiddle their tax.....pay their plumbers/builders/cleaners cash to save VAT?
As the director of a micro business, I only accept online payments and cheques, as a vat registered business and an honest person I am astounded by the number of potential clients who ask for a discount for cash. I point out, not always politely, that the VAT is not my money, and could they explain to me why I should commit a crime, a fraud, just to save them 20%? 
Also, as an employer, I pay SSP to my employees, and this is not reimbursed or offfset against NIC payments, I cannot pay it to myself, so fail to see why I should pay the same NIC.