Mixture of LTO 5 and 6 in SLES11 SP2

SLES11 SP2 appears to be having difficulties recognizing the full 8-alphanumeric (ex. 000007L5) barcode on a LTO5 tape. Currently, it appears to only sees the first 6 digits. The reason I say this is because there is a mixture of LTO5 and LTO6 tape in the library with the same barcode numbers (i.e. 000001L5, 000001L6, etc) and when I issue the command mtlib -l/dev/IBMchanger0 -m -f/dev/IBMtape14 -V000007L5 -v, it looks like the LTO5 tape is being loaded into the drive but in fact the LTO6 tape gets loaded.

My setup is as follows: IBM TL4000 tape library with 4-3580 tape drives, lintape 1.76, ibmatl, SLES11 SP2

Is this there a way for mtlib to recognize the last 2 characters (i.e. cli switch) of the barcode or do I have to use some other utlity for this to be achieved?
Thanks in advance.