check "Utility Guide and Reference" manual for V8, page 579 where say about " &variable". More specificaly where says:
"To specify a substring, use the form &variable(start). or &variable(start,length)."
Based on this info was expected the result mentioned before.
Example 2: Using variable substring notation to specify data set names. The following control statement defines template CP2. Variable substring notation is used in the DSN option to define the data set naming convention.
Assume that in the year 2003 you make a full image copy of partition 00004 of table space DSN8S81D. Assume that you specify the template CP2 for the data set for the local primary copy. DB2 gives the following name to the image copy data set: DH173001.DSN8S81D.Y03.COPYLP.P004
Notice that every variable in the DSN option begins with an ampersand (&) and ends with a period (.). These ampersands and periods are not included in the data set name. Only periods that do not signal the end of a variable are included in the data set name.
Example 3: Using COPY with TEMPLATE with variable substring notation. The following TEMPLATE utility control statement defines template SYSCOPY. Variable substring notation is used in the DSN option to define the data set naming convention. The subsequent COPY utility control statement specifies that DB2 is to make a local primary copy of the first partition of table space DSN8D81A.DSN8S81E. COPY is to write this image copy to a data set that is dynamically allocated according to the SYSCOPY template. In this case, the resulting data set name is DSN8D81A.DSN8S81E.P001
Notice that you can change the part variable in the DSN operand from P&PA(3). to P&PA(3,3). The resulting data set name is the same, because the length value of 3 is implied in the first specification.
These look more like the dsns you want to create. Notice, they used 3 rather than 4 or 4,2. You might give it a try with 2 and see if you get what you are looking for.