2008/01/01 * (100) January
    Expenses:Books          $10.00
    Assets:Cash

2008/01/31 (101) End of January
    Expenses:Books          $10.00
    Assets:Cash

2008/02/01 * (102) February
    Expenses:Books          $20.00
    Assets:Cash

2008/02/28 (103) End of February
    Expenses:Books          $20.00
    Assets:Cash

2008/03/01 * March
    Expenses:Books          $30.00
    Assets:Cash

test reg --account=code
08-Jan-01 January               100:Expenses:Books           $10.00       $10.00
08-Jan-01 January               100:Assets:Cash             $-10.00            0
08-Jan-31 End of January        101:Expenses:Books           $10.00       $10.00
08-Jan-31 End of January        101:Assets:Cash             $-10.00            0
08-Feb-01 February              102:Expenses:Books           $20.00       $20.00
08-Feb-01 February              102:Assets:Cash             $-20.00            0
08-Feb-28 End of February       103:Expenses:Books           $20.00       $20.00
08-Feb-28 End of February       103:Assets:Cash             $-20.00            0
08-Mar-01 March                 Expenses:Books               $30.00       $30.00
08-Mar-01 March                 Assets:Cash                 $-30.00            0
end test