Errors not affecting trial balance can take several forms.
For example, a transaction may be entered in the subsidiary book at the wrong amount (i.e., error in original entry) and later debited or credited to the wrong account in the ledger (i.e., error of commission).
As another example, an item of capital expenditure may be treated as an item of revenue expenditure and, at the same time, the entries may be made in the ledger on the wrong sides of the accounts involved (i.e., complete reversal of entries).
The above errors, as well as other errors like these, should be treated as two errors. As such, two separate rectification entries should be passed to rectify them.
An invoice for $1,450 was issued to Mr. Tom. It was entered at $1,400 in the sales book and later debited to Tom & Company’s account.
These are obviously two errors. First, there is an error in the original entry when an invoice for $1,450 was recorded in the sales book at $1,400. The second error occurred when Tom & Company’s account was debited instead of Mr. Tom’s account.
As a result of the above two entries, the total credit in the sales account increases from $1,400 to $1,450 (i.e., the correct amount of the invoice).
At the same time, the debit entry of $1,400 is removed from Tom & Company’s account, while Mr. Tom’s account is debited with a total of $1,450, which is the correct amount of the invoice.