LTE support for 3 BCD digit network codes

[kevin]

Is there a way to make the SQNS modem read a 3-digit network code (MNC) from the SIM as part of the PLMN?

The AT+SQNHPLMN command reference is a bit ambiguous, since it refers to "a two BCD digit network code" but shows the overall PLMN format as "(country digit3)(country digit2)(country digit1)(network digit3)(network digit2)(network digit1)".

Our network PLMN is 313-490 (3-digit MNCs are common in the U.S.). However, after attach, the modem reports it is roaming because it did not pick up the 3rd MNC digit from the SIM card:

'AT+SQNHPLMN?'
+SQNHPLMN: "31349","31349","31349"
OK
'AT+CEREG?'
+CEREG: 0,5
OK

Has anyone else attached to a network with 6-digit PLMN? Any trick to force in that last MNC digit?