what method was used on the amended returns? if it was changed from cash to accrual, why? what year is the LLC on for tax reporting purposes?
if the accrual method was used on the amended returns for 2015 and 2016 you need to file for a change in accounting methods form 3115 which goes with the return that's being changed. see the instructions for where and when a signed copy must be filed. This is separate from the copy that goes with the return..
if the LLC is on a calendar year, regardless of whether it's a single or multi-member, the return is late and the accounting method change can't be done until the 2018 calendar year.
seek professional help, the form is tricky
but to answer your basic question, you apparently do not have inventories and I assume not a tax shelter so you would qualify for an automatic change (in the proper year)
tax shelter:
(A) any enterprise (other than a
C corporation) if at any time interests in such enterprise have been offered for sale in any offering required to be registered with any Federal or State agency having the authority to regulate the offering of securities for sale,
even if you had inventory, with annual gross receipts under $1,000,000 you would still qualify for the cash method. but again assuming the business is not a tax shelter
it is quite common for businesses to keep their books on the accrual method to see how they're doing financially, while using the cash method for tax reporting.
