SNMP is not pulling the correct data for the classByteCount OID when the bandwidth utilization is more than 60M.

Because PacketWise uses 32-bit counters, there are two OIDs: classByteCount and classByteCountHi. classByteCount is the lower 32-bit counter and classByteCountHi is the higher 32-bit counter. By combining these two values, you should be able to get the actual ByteCount (64-bit).