diff --git a/grey/crates/grey-services/src/accumulation.rs b/grey/crates/grey-services/src/accumulation.rs
index 14b871452..7718eab8e 100644
--- a/grey/crates/grey-services/src/accumulation.rs
+++ b/grey/crates/grey-services/src/accumulation.rs
@@ -382,13 +382,11 @@ pub fn integrate_preimages(
     }
 }
 
-/// Collect the set of work-package hashes from accumulated reports (P function).
+/// Collect the set of work-package hashes from the first `count` reports (P function).
+///
+/// Delegates to [`grey_state::accumulate::package_hashes`] after truncating to `count`.
 pub fn accumulated_package_hashes(reports: &[WorkReport], count: usize) -> BTreeSet<Hash> {
-    reports
-        .iter()
-        .take(count)
-        .map(|r| r.package_spec.package_hash)
-        .collect()
+    grey_state::accumulate::package_hashes(&reports[..count.min(reports.len())])
 }
 
 #[cfg(test)]
diff --git a/grey/crates/grey-state/src/accumulate.rs b/grey/crates/grey-state/src/accumulate.rs
index 1f4d18348..d0903b023 100644
--- a/grey/crates/grey-state/src/accumulate.rs
+++ b/grey/crates/grey-state/src/accumulate.rs
@@ -220,7 +220,7 @@ fn partition_reports(reports: &[WorkReport]) -> (Vec<WorkReport>, Vec<ReadyRecor
 }
 
 /// Extract work-package hashes from reports (eq 12.9).
-fn package_hashes(reports: &[WorkReport]) -> BTreeSet<Hash> {
+pub fn package_hashes(reports: &[WorkReport]) -> BTreeSet<Hash> {
     reports
         .iter()
         .map(|r| r.package_spec.package_hash)