strange SRB_FUNCTION value

Does anyone know what 0xc8 may mean in

PSCSI_REQUEST_BLOCK Srb = irpSp->Parameters.Scsi.Srb;
// here Srb->Function is 0xc8 from time to time

srb.h defines SRB_FUNCTION_EXECUTE_SCSI as 0 and
SRB_FUNCTION_UNLOCK_QUEUE as 0x19
with the rest in between.

One of OSR help pages mentions SRB_FUNCTION_LOGICAL_UNIT_RESET
that I could not find in any of the DDK headers (3790.1830) - is that it?

Any advice is appreciated.

Regards,
Alex