Chinese Characters Printing as Boxes in SAPscript

Question

Issue...why would a Chinese standard text print fine using the "INCLUDE" method, but output as boxes when that same Chinese standard text is retrieved successfully using the "PERFORM" method?
Summary...I am currently experiencing problems printing Chinese characters on a custom SAP Script form. This does not appear to be an issue with printer setup or font selection, as I am able to get the Chinese characters to appear depending on the method I use. The problem occurs when I execute a "PERFORM" within the SAP script to retrieve the Chinese standard text, the results are displayed as boxes. If I "INCLUDE" the standard text directly within the SAP script, the Chinese standard text prints without issue. I have executed the SAP script in debug mode and the Chinese text is being retrieved from the "PERFORM" statement as expected, but just does not display correctly as it does by using the "INCLUDE" approach. I'm trying to understand why the two approaches would not both work in the same manner. We are on a UNICODE system.
Though we may be able to use the "INCLUDE" method in a majority of places, we are interested in using the function "ADDRESS_INTO_PRINTFORM" for printing addresses. This would require passing values back to the SAP script line by line.
Below is a simplified version of the two methods...
(PRINTS CHINESE CHARACTERS AS EXPECTED)
INCLUDE 'ZADDRESS_LINE1' OBJECT 'TEXT' ID 'ST' LANGUAGE &NAST-SPRAS& PARAGRAPH IG
(RESULTS IN BOXES BEING PRINTED)
PERFROM GET_TEXT IN PROGRAM ZGET_CHINESE_TEXT
USING &NAST-SPRAS&
CHANGING &ADDRESS_LINE1&
ENDPERFORM.
&ADDRESS_LINE1&
(&ADDRESS_LINE1& contains Chinese characters as expected when debugging SAP script)
FORM GET_TEXT TABLE PT_IN STRUCTURE ITCSY
PT_OUT STRUCTURE ITCSY
...USE FUNCTION 'READ_TEXT' TO RETRIEVE CHINESE TEXT FROM ZADDRESS_LINE1 STANDARD TEXT (works as expected)
read table pt_out index 1.
move ADDRESS_LINE1 to pt_out-value.
modify pt_out index 1.
(PT_OUT table is populated with chinese text as expected)
ENDFORM.

Answer 1

Language for form is 'ZH'.
To clarify the original post, the standard text is being retrieved correctly for both methods.  By this I mean that during debugging of the SAP script I can see the Chinese text as expected for both methods.  However, during print preview only the "INCLUDE" method displays correctly.  I have both methods included in my current script for the same standard text and the "INCLUDE" displays fine, but not the "PERFORM" method.
Does the "CHANGING" parameter which is populated by the "PERFORM" need to be defined in a particular way?  Might there an issue with the TDSYMVALUE type that is used for storing the values retrieved from the "PERFORM"?