ORA-55734
The SET clause of a reservable column update statement requires a single expression value to be added or subtracted from the same reservable column.
Cause
The amount to be added or subtracted from a reservable column is not provided as a single expression.
Action
Change the update statement by adding parenthesis to specify a single expression that should be added or subtracted from the reservable column. The SET clause should be of the form reservable_col1 = reservable_col1 + (expression) or reservable_col1 = reservable_col1 - (expression)."