Query regarding exemption availabl to small service provider

The exemption notification says that SSI exemption will be available on first consequitive invoices amounting to Rs 10 lacs. May be you can revise the bills if possible. because once service tax is collected it has to be paid to department. And if in audit the officer finds out that SSI has been claimed on some invoices and not on some, he is certainly going to show you the notification. If there are any case laws, I may not be aware of it but in my opinion, there is no way out except revising invoices if possible.