diff --git a/change_sync_bias.py b/change_sync_bias.py
index 46bb089..a918181 100644
--- a/change_sync_bias.py
+++ b/change_sync_bias.py
@@ -1,10 +1,29 @@
+R"""
+Add or subtract the standard ITG sync bias (9 milliseconds)
+to all of the sync offsets in a pack.
+
+This script updates the offsets of both SM and SSC simfiles,
+including any SSC charts with their own timing data.
+
+If you actually intend to use this script in practice,
+you may want to keep track of which packs you've already adjusted
+using a text file in each pack directory or some other system.
+
+Usage examples:
+
+    # Convert a pack from "null sync" to "ITG sync"
+    python change_sync_bias.py +9 "C:\StepMania\Songs\My Pack"
+
+    # Convert a pack from "ITG sync" to "null sync"
+    python change_sync_bias.py -9 "C:\StepMania\Songs\My Pack"
+"""
 import argparse
 from decimal import Decimal
 import sys
 from typing import Union
 
 import simfile
-from simfile.dir import SimfilePack
+import simfile.dir
 
 
 class ChangeSyncBiasArgs:
@@ -58,6 +77,8 @@ def change_sync_bias(simfile_path: str, args: ChangeSyncBiasArgs):
         input_filename=f"{simfile_path}",
         backup_filename=f"{simfile_path}~",
     ) as sf:
+        print(f"Processing {simfile_path}")
+
         # Always adjust the simfile's offset
         adjust_offset(sf, delta)
 
@@ -74,7 +95,7 @@ def main(argv):
 
     # Iterate over SimfileDirectory objects from the pack
     # so that we can easily get the .sm and/or .ssc paths
-    for simfile_dir in SimfilePack(args.pack).simfile_dirs():
+    for simfile_dir in simfile.dir.SimfilePack(args.pack).simfile_dirs():
 
         # Try to update whichever formats exist
         for simfile_path in [simfile_dir.sm_path, simfile_dir.ssc_path]: