So long as you are following generally accepted accounting principles (GAAP), it really doesn't matter what you use for record keeping. You can do it by hand if you wish. I don't know whether you are operating on a cash or accrual basis... I think IRAS requires accrual basis (but you need to check), and accrual basis accounting is certainly a cornerstone of GAAP.
You should go to the IRAS website and download a copy of the annual tax return required for all pte ltd's. If you can fill out all of the form properly, then your records are sufficient since this form requires you to supply P&L, balance sheet, cash flow, and other reconciliation items.
You also need to go to the ACRA website and check out the BizFile filing requirements. Financially, they will want a summary of what you file with IRAS. I forget all of the details in the BizFile filing... I think it's mostly directors, shareholders, and note of lawsuits, bankruptcies, etc.
If you are a sole director, you MUST, by law, have an outside secretary, at least in name. You must have at least one AGM per your memorandum of incorporation. You must record all directors resolutions, minutes, etc. As an EPC you don't need to file these anywhere, just keep a record. As a sole shareholder/owner, no one is every going to demand to see your record books; however, your failure to keep these records could destroy your corporate shield, and potentially leave you open to penalties for failure to maintain records... I say potentially because it is unlikely that you will sue yourself and also unlikely that someone else will.
You must file your annual report with BizFile, as above. See
https://www.acra.gov.sg/BizFile/ for more information. All the filings are standardized on the website... I think you can even upload certain file types but it has been a few years for me.
You don't need an audited return unless a bank or government agency has requested it as a condition of a loan or some such. Your directors statements are simple... you mostly state (under penalties for lying) that the financial condition is as you stated, that you have the noted shareholders and directors, that you are not subject to a lawsuit, etc. With unaudited books there are many situations that you do not need to address, such as contingent liabilities
A final note: Keep all history of all transactions. Scan original documents. so they don't fade. Should you ever be audited, transaction histories make all the difference in proving your status.
