diff --git a/timing/timing.c b/timing/timing.c
index 519cee03d9e610195fb3d1d7632702703e48cb36..54680c32f7abf62f86452b6ff5684058c7f245de 100644
--- a/timing/timing.c
+++ b/timing/timing.c
@@ -597,9 +597,9 @@ parse_arguments(int *_argc, char ***_argv, int *iparam, int *start, int *stop, i
         case 'a' : iparam[IPARAM_RHBLK         ] = atoi(optarg); break;
         case 'P' : iparam[IPARAM_P             ] = atoi(optarg); break;
         case 'M' : iparam[IPARAM_MODE          ] = atoi(optarg); break;
-        case 'b' : iparam[IPARAM_NB            ] = atoi(optarg);
-                   iparam[IPARAM_MB            ] = atoi(optarg); break;
-        case 'n' : get_range(optarg, start, stop, step); break;
+        case 'n' : iparam[IPARAM_NB            ] = atoi(optarg); break;
+        case 'm' : iparam[IPARAM_MB            ] = atoi(optarg); break;
+        case 'N' : get_range(optarg, start, stop, step); break;
         case 'h' : show_help(argv[0]); break;
         default:
             break;