COBCH1622 A SIZE OF expression cannot be used as a receiving item

You have attempted to use the SIZE OF expression as part of a receiving item.

In this COBOL system, you can only use the SIZE OF expression as a sending item. For example:

01 firstName string
01 totalLen pic 9(3).
...
add 10 to SIZE OF firstName.                *> this is incorrect
add SIZE OF firstName to totalLen.	    *> this is correct

Note: You can only use the SIZE OF expression with single-dimensional managed arrays or strings.