Why don't these two commands produce the same results?

[Karl Fogel]

I may be misunderstanding how the '-p' option works... Can anyone
explain why these two commands don't give exactly the same results?  I
would have thought they both produce simple balance sheets for 2010,
but apparently they're not doing exactly the same thing:

  prompt> ledger -p 2010 -f main.ledger -s bal assets liabilities
             $7,602.75  Assets
            $16,740.70    Checking
             $1,051.60    Google
              $-248.55    PayPal
                $59.00    QCC
            $30,000.00    Receivables
           $-40,000.00    Savings
            $16,455.81  Liabilities
             $1,335.50    Due to/from Karl Fogel
            $13,366.92    Due to/from Nina Paley
             $1,753.39    Due to/from SSTB Musicians
  --------------------
            $24,058.56


  prompt> ledger -b 2010/01/01 -e 2010/12/31 -f main.ledger -s bal
assets liabilities
             $7,638.24  Assets
            $16,740.70    Checking
             $1,051.60    Google
              $-213.06    PayPal
                $59.00    QCC
            $30,000.00    Receivables
           $-40,000.00    Savings
            $12,312.81  Liabilities
             $1,335.50    Due to/from Karl Fogel
             $9,458.92    Due to/from Nina Paley
             $1,518.39    Due to/from SSTB Musicians
  --------------------
            $19,951.05

Thanks,
-Karl