Another way to explain this is that you can only use the small business deduction for an insurance policy you buy in your own name or in the name of the business. An employer-sponsored policy is not eligible even if you paid 100% of the premium. If you start your business on July 1 (for example) I doubt that you would buy a policy that was backdated to January 1.
On the other hand, "registering" a business with your county or state is not necessarily when the business "started". Your business starts when it becomes an ongoing trade or business activity for the purpose of making a profit, and you are required to report all your business income and expenses, even if the business is not registered with some government agency. For example, if you want to do landscaping and lawn mowing, and you start canvassing neighborhoods and posting ads in April, that is when the business started, even if you did not get your first paying customer until May or did not get a local business license until July.
