diff --git a/specs/phase0/beacon-chain.md b/specs/phase0/beacon-chain.md
index 82fbb2856..fe8fcc9bd 100644
--- a/specs/phase0/beacon-chain.md
+++ b/specs/phase0/beacon-chain.md
@@ -1370,8 +1370,8 @@ def get_attestation_component_deltas(state: BeaconState,
     """
     Helper with shared logic for use by get source, target, and head deltas functions
     """
-    rewards = [Gwei(0) for _ in range(len(state.validators))]
-    penalties = [Gwei(0) for _ in range(len(state.validators))]
+    rewards = [Gwei(0)] * len(state.validators)
+    penalties = [Gwei(0)] * len(state.validators)
     total_balance = get_total_active_balance(state)
     unslashed_attesting_indices = get_unslashed_attesting_indices(state, attestations)
     attesting_balance = get_total_balance(state, unslashed_attesting_indices)
diff --git a/tests/core/pyspec/eth2spec/test/helpers/rewards.py b/tests/core/pyspec/eth2spec/test/helpers/rewards.py
index deee1b120..6e470d9e9 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/rewards.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/rewards.py
@@ -1,12 +1,13 @@
 from random import Random
 
+from eth2spec.phase0 import spec as spec_phase0
 from eth2spec.test.helpers.attestations import prepare_state_with_full_attestations
 from eth2spec.utils.ssz.ssz_typing import Container, uint64, List
 
 
-# HACK to get the generators outputting correctly
 class Deltas(Container):
-    delta_list: List[uint64, 2**30]
+    rewards: List[uint64, spec_phase0.VALIDATOR_REGISTRY_LIMIT]
+    penalties: List[uint64, spec_phase0.VALIDATOR_REGISTRY_LIMIT]
 
 
 def has_enough_for_reward(spec, state, index):
@@ -33,8 +34,7 @@ def run_attestation_component_deltas(spec, state, component_delta_fn, matching_a
 
     rewards, penalties = component_delta_fn(state)
 
-    yield 'rewards', Deltas(delta_list=rewards)
-    yield 'penalties', Deltas(delta_list=penalties)
+    yield 'deltas', Deltas(rewards=rewards, penalties=penalties)
 
     matching_attestations = matching_att_fn(state, spec.get_previous_epoch(state))
     matching_indices = spec.get_unslashed_attesting_indices(state, matching_attestations)
diff --git a/tests/core/pyspec/eth2spec/test/phase_0/rewards/test_get_inactivity_penalty_deltas.py b/tests/core/pyspec/eth2spec/test/phase_0/rewards/test_get_inactivity_penalty_deltas.py
index fb24e09d8..657acbdbb 100644
--- a/tests/core/pyspec/eth2spec/test/phase_0/rewards/test_get_inactivity_penalty_deltas.py
+++ b/tests/core/pyspec/eth2spec/test/phase_0/rewards/test_get_inactivity_penalty_deltas.py
@@ -1,13 +1,8 @@
 from eth2spec.test.context import with_all_phases, spec_state_test
 from eth2spec.test.helpers.rewards import has_enough_for_reward
 from eth2spec.test.helpers.state import next_epoch
+from eth2spec.test.helpers.rewards import Deltas
 import eth2spec.test.helpers.rewards as rewards_helpers
-from eth2spec.utils.ssz.ssz_typing import Container, uint64, List
-
-
-# HACK to get the generators outputting correctly
-class Deltas(Container):
-    delta_list: List[uint64, 2**30]
 
 
 def run_get_inactivity_penalty_deltas(spec, state):
@@ -22,8 +17,7 @@ def run_get_inactivity_penalty_deltas(spec, state):
 
     rewards, penalties = spec.get_inactivity_penalty_deltas(state)
 
-    yield 'rewards', Deltas(delta_list=rewards)
-    yield 'penalties', Deltas(delta_list=penalties)
+    yield 'deltas', Deltas(rewards=rewards, penalties=penalties)
 
     matching_attestations = spec.get_matching_target_attestations(state, spec.get_previous_epoch(state))
     matching_attesting_indices = spec.get_unslashed_attesting_indices(state, matching_attestations)
diff --git a/tests/core/pyspec/eth2spec/test/phase_0/rewards/test_get_inclusion_delay_deltas.py b/tests/core/pyspec/eth2spec/test/phase_0/rewards/test_get_inclusion_delay_deltas.py
index 9eda75290..320f59a9d 100644
--- a/tests/core/pyspec/eth2spec/test/phase_0/rewards/test_get_inclusion_delay_deltas.py
+++ b/tests/core/pyspec/eth2spec/test/phase_0/rewards/test_get_inclusion_delay_deltas.py
@@ -2,14 +2,8 @@ from random import Random
 
 from eth2spec.test.context import with_all_phases, spec_state_test
 from eth2spec.test.helpers.attestations import prepare_state_with_full_attestations
-from eth2spec.test.helpers.rewards import has_enough_for_reward
+from eth2spec.test.helpers.rewards import Deltas, has_enough_for_reward
 import eth2spec.test.helpers.rewards as rewards_helpers
-from eth2spec.utils.ssz.ssz_typing import Container, uint64, List
-
-
-# HACK to get the generators outputting correctly
-class Deltas(Container):
-    delta_list: List[uint64, 2**30]
 
 
 def run_get_inclusion_delay_deltas(spec, state):
@@ -24,8 +18,7 @@ def run_get_inclusion_delay_deltas(spec, state):
 
     rewards, penalties = spec.get_inclusion_delay_deltas(state)
 
-    yield 'rewards', Deltas(delta_list=rewards)
-    yield 'penalties', Deltas(delta_list=penalties)
+    yield 'deltas', Deltas(rewards=rewards, penalties=penalties)
 
     eligible_attestations = spec.get_matching_source_attestations(state, spec.get_previous_epoch(state))
     attesting_indices = spec.get_unslashed_attesting_indices(state, eligible_attestations)
diff --git a/tests/formats/rewards/README.md b/tests/formats/rewards/README.md
index dce2b5ac8..bffe2e7de 100644
--- a/tests/formats/rewards/README.md
+++ b/tests/formats/rewards/README.md
@@ -4,7 +4,6 @@ The different rewards deltas sub-functions are testing individually with the tes
 There is no "change" factor, the rewards/penalties outputs are pure functions with just the pre-state as input.
 Hence, the format is shared between each test-handler. (See test condition documentation on how to run the tests.)
 
-
 ## Test case format
 
 ### `meta.yaml`
@@ -12,23 +11,29 @@ Hence, the format is shared between each test-handler. (See test condition docum
 ```yaml
 description: string    -- Optional description of test case, purely for debugging purposes.
                           Tests should use the directory name of the test case as identifier, not the description.
-bls_setting: int       -- see general test-format spec.
 ```
 
+_Note_: No signature verification happens within rewards sub-functions. These
+ tests can safely be run with or without BLS enabled.
+
 ### `pre.yaml`
 
 A YAML-encoded `BeaconState`, the state before running the rewards sub-function.
 
 Also available as `pre.ssz`.
 
+### `deltas.yaml`
 
-### `rewards.yaml`
+A YAML-encoded `Deltas` representing the rewards and penalties returned by the rewards sub-function
 
-A YAML-encoded list of integers representing the 0th item in the return value (i.e. the rewards deltas)
+Where `Deltas` is defined as:
+```python
+class Deltas(Container):
+    rewards: List[uint64, VALIDATOR_REGISTRY_LIMIT]
+    penalties: List[uint64, VALIDATOR_REGISTRY_LIMIT]
+```
 
-### `penalties.yaml`
-
-A YAML-encoded list of integers representing the 1st item in the return value (i.e. the penalties deltas)
+Also available as `rewards.ssz`.
 
 ## Condition
 
@@ -38,10 +43,10 @@ This excludes all other parts of `process_rewards_and_penalties`
 
 The provided pre-state is ready to be input into the designated handler.
 
-The resulting `rewards`/`penalties` should match the return values of the
-handler. Specifically the following must hold true:
+The provided `deltas` should match the return values of the
+ handler. Specifically the following must hold true:
 
 ```python
-    rewards == handler(state)[0]
-    penalties == handler(state)[1]
+    deltas.rewards == handler(state)[0]
+    deltas.penalties == handler(state)[1]
 ```