diff --git a/specs/phase0/fork-choice.md b/specs/phase0/fork-choice.md
index 497c06dc6..fe546142b 100644
--- a/specs/phase0/fork-choice.md
+++ b/specs/phase0/fork-choice.md
@@ -181,11 +181,13 @@ def get_latest_attesting_balance(store: Store, root: Root) -> Gwei:
         if (i in store.latest_messages
             and get_ancestor(store, store.latest_messages[i].root, store.blocks[root].slot) == root)
     ))
+    if store.proposer_boost_root == Root():
+        # Return only attestation score if ``proposer_boost_root`` is not set
+        return attestation_score
+    # Calculate proposer score if ``proposer_boost_root`` is set
     proposer_score = Gwei(0)
-    if (
-        store.proposer_boost_root != Root()
-        and get_ancestor(store, store.proposer_boost_root, store.blocks[root].slot) == root
-    ):
+    # Boost is applied if ``root`` is an ancestor of ``proposer_boost_root``
+    if get_ancestor(store, store.proposer_boost_root, store.blocks[root].slot) == root:
         num_validators = len(get_active_validator_indices(state, get_current_epoch(state)))
         avg_balance = get_total_active_balance(state) // num_validators
         committee_size = num_validators // SLOTS_PER_EPOCH