yes 3115 is required, there is another issue when accounting for inventory as other than incidental materials and supplies that will probably require the use of the accrual method of accounting. sales will be recognized as income when made not when proceeds are received. and an expenses when incurred rather than when paid
from the iRS.
If you purchase or manufacture goods that produce income for your business, you may not be able to use the cash method of accounting. You can choose to use the accrual method for all of your accounting, but you also can choose a hybrid method of accounting. Under the hybrid method, you use the accrual system for sales and inventory purchases.
this is a complex step, so the use of a pro is advisable. since there will likely be a section 481 adjustment.
you probably have another option. accounting software like Quickbooks and Mint will allow you to see how your business is doing on an accrual basis but allow you to switch over the cash basis for tax reporting. but the books have to be set up right
