Is it possible to Simplify 2 Selects, maybe into 1 as they add a bit of time when used in a Stored Procedure and called many times?

/* Get Our OVER Spent Codes */
select SUM(Cmt.BALANCE_TD)
from CODES_MONTHLY_TABLE Cmt
WHERE (Cmt.id = :ip_id) and (Cmt.BALANCE_TD < 0) and ((Cmt.THEMONTH - 1) = :ip_currentmonth)
into :op_overspent_codes;

/* Get Our UNDER Spent Codes */
select SUM(Cmt.BALANCE_TD)
from CODES_MONTHLY_TABLE Cmt
WHERE (Cmt.id = :ip_id) and (Cmt.BALANCE_TD > 0) and ((Cmt.THEMONTH - 1) = :ip_currentmonth)
into :op_underspent_codes;

The table CODES_MONTHLY_TABLE is quite large and I have an index on the field
Cmt.id.

These are input parameters:-

:ip_id

:ip_currentmonth

tia