def credit_column
    base = cash_sales + accounting_credit + amex_total + newbook_total + usedbook_total + coursepack_total + reference_total + insignia_total + food_total + office_total + greek_total + medref_total + medsup_total + shipping_total + taxes_total + wholesales + advertisings + credit_bal_refunds + bad_check_redeposits + misc_cashes + settlements + commissions + eagle_checks + petty_cash_adj
    if positive_giftcards && negative_on_account
      base + giftcard_total + net_on_account
    elsif positive_giftcards
      base + giftcard_total
    elsif negative_on_account
      base + net_on_account
    else
      base
    end
  end