diff --git a/src/fsrs_optimizer/fsrs_optimizer.py b/src/fsrs_optimizer/fsrs_optimizer.py
index 24151aa..a254d08 100644
--- a/src/fsrs_optimizer/fsrs_optimizer.py
+++ b/src/fsrs_optimizer/fsrs_optimizer.py
@@ -166,9 +166,10 @@ def __call__(self, module):
         if hasattr(module, "w"):
             w = module.w.data
             w[0] = w[0].clamp(S_MIN, 100)
-            w[1] = w[1].clamp(w[0] * 1.05, 100)
-            w[2] = w[2].clamp(w[1] * 1.05, 100)
-            w[3] = w[3].clamp(w[2] * 1.05, 100)
+            # this ensures that w[n] is at least 5% greater than w[n-1], and also greater by at least 1 hour
+            w[1] = w[1].clamp(max(w[0] * 1.05, w[0] + 0.05), 100)
+            w[2] = w[2].clamp(max(w[1] * 1.05, w[1] + 0.05), 100)
+            w[3] = w[3].clamp(max(w[2] * 1.05, w[2] + 0.05), 100)
             w[4] = w[4].clamp(1, 10)
             w[5] = w[5].clamp(0.01, 4)
             w[6] = w[6].clamp(0.01, 4)