NOT ON SIZE ERROR
If the NOT ON SIZE ERROR phrase has been specified and, after execution of an arithmetic operation, a size error condition does not exist, the NOT ON SIZE ERROR phrase is executed.
When both ON SIZE ERROR and NOT ON SIZE ERROR phrases are specified, and the statement in the phrase that is executed does not contain any explicit transfer of control, then, if necessary, an implicit transfer of control is made after execution of the phrase to the end of the arithmetic statement.