Resolve error that Get Range length is wrong for IMpb "IMpb length mismatch" in Mail360 Manager (or Mail360 Server)



IMpb serial number lengths can either be short or long.  The first time you make a call for a specific Mailer ID, it creates a record in the Mail360 Manager's 'DS' file (which is where serial numbers are kept track of.)  The 'DS' file may be called G1IMB.DS or G1IMBDS, or the DD will be G1IMBDS, depending on the platform being used.
The line will look like this for Mailer ID 123456 if short serial numbers were requested-
The 's' after the 'p' means that short IMpb serial numbers are and will be be used for Mailer ID 123456.

If a later job for that Mailer ID wants to get IMpb 'long' serial numbers for the same Mailer ID, then an error will occur, saying that the defined length in the DS file is an S, and the (long serial number) request does not match.

For example, in the execution log from MailStream Plus it would end with these lines-
10/21/2015  16:35:19 TESTPREM   MSNA00A    I ERROR E0001 when calling MAIL360  GetRange for Mailer ID  123456
10/21/2015  16:35:19 TESTPREM   MSNA00A    I IMpb length mismatch : S.
10/21/2015  16:35:19 TESTPREM   MSNA00A    I
10/21/2015  16:35:19 TESTPREM   MSNA00A    I
10/21/2015  16:35:19 TESTPREM   MSNA00A    E
10/21/2015  16:35:19 TESTPREM   MSDR01     I MSDR01 Ended abnormally. Processing terminated.
10/21/2015  16:35:19 TESTPREM   G1DRIVER4  E Abnormal Termination detected -- execution abandoned

or vice versa, if the first call was for a long IMpb serial number, the DS record will look like this-
and if a later job tries to get a short one, then the error will say-
10/26/2015  15:59:01            MSNA00B    I ERROR E0001 when calling MAIL360  GetRange for Mailer ID  123456
10/26/2015  15:59:01            MSNA00B    I IMpb length mismatch : L


Manager will not let you switch lengths for a Mailer ID's IMpbs, or create two records for both short and long, because either situation could lead improperly to duplicate serial numbers being used.


UPDATED: August 7, 2017
Depending on the Mailer's situation, there are possible work-arounds-
1) Continue to use the IMpb length that was originally setup for that Mailer ID.
2) Change the s to a letter l (or vice versa) on that line in the DS file, so Manager will start generating the other length serial numbers starting with the next available serial number. 
3) Erase the line in the DS file and let Manager create a new line for the other serial number length.  Keeping in mind that this option will re-start the serial numbers for the Mailer ID at '1'.