diff --git a/src/re/multi_grid/grid_impl.py b/src/re/multi_grid/grid_impl.py
index 535045d8259f78cb3a067d7a950d90130117afa9..6b26670cf44f6983ef4600885c5e32f5431a1c9b 100644
--- a/src/re/multi_grid/grid_impl.py
+++ b/src/re/multi_grid/grid_impl.py
@@ -324,8 +324,8 @@ class LogarithmicGridAtLevel(SimpleOpenGridAtLevel):
 
     def index2volume(self, index):
         a = (slice(None),) + (np.newaxis,) * index.ndim
-        coords = super().index2coord(index + jnp.array([-0.5, 0.5])[a])
-        return jnp.prod(coords[1] - coords[0], axis=0)
+        coords = self.index2coord(index + jnp.array([-0.5, 0.5])[a])
+        return coords[1] - coords[0]
 
 
 def LogarithmicGrid(
@@ -362,6 +362,9 @@ class HPLogRGridAtLevel(MGridAtLevel):
         r = jnp.linalg.norm(coord, axis=0)[jnp.newaxis, ...]
         coord = jnp.concatenate((coord / r, r), axis=0)
         return super().coord2index(coord, **kwargs)
+    
+    def index2volume(self, index):
+        raise NotImplementedError("Volume calculation not implemented for HPLogRGrid")
 
 
 def HPLogRGrid(