diff --git a/Cargo.toml b/Cargo.toml
index 9abe9e379a2..199796a32c5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -158,7 +158,8 @@ datafusion-sqllogictest = { version = "54" }
 divan = { package = "codspeed-divan-compat", version = "5.0.0" }
 enum-iterator = "2.0.0"
 env_logger = "0.11"
-fastlanes = "0.6.0"
+# Pinned: fastlanes 0.6.2 changed the bit-transpose API and breaks the lock-free wasm-test build.
+fastlanes = "=0.6.1"
 flatbuffers = "25.2.10"
 fsst-rs = "0.6.0"
 futures = { version = "0.3.31", default-features = false }
diff --git a/scripts/compare-benchmark-jsons.py b/scripts/compare-benchmark-jsons.py
index ffd899b55b5..8124b9464e6 100644
--- a/scripts/compare-benchmark-jsons.py
+++ b/scripts/compare-benchmark-jsons.py
@@ -861,8 +861,9 @@ def format_file_size_report(base_rows: pd.DataFrame, pr_rows: pd.DataFrame) -> s
         return ""
 
     base_data = {key: value for key, value in base_data.items() if key not in ignored}
-    pr_scopes = {(benchmark, scale_factor) for benchmark, scale_factor, _file_format, _file_name in pr_data}
-    base_data = {key: value for key, value in base_data.items() if key[:2] in pr_scopes}
+    # Omit baseline files whose (benchmark, scale factor, format) the PR run skipped entirely.
+    pr_scopes = {(benchmark, scale_factor, file_format) for benchmark, scale_factor, file_format, _file_name in pr_data}
+    base_data = {key: value for key, value in base_data.items() if key[:3] in pr_scopes}
     if not base_data:
         return "_No baseline file sizes found for base commit._"
 
diff --git a/scripts/tests/test_benchmark_reporting.py b/scripts/tests/test_benchmark_reporting.py
index 024d5b75e67..e2b829f1d86 100644
--- a/scripts/tests/test_benchmark_reporting.py
+++ b/scripts/tests/test_benchmark_reporting.py
@@ -662,6 +662,29 @@ def test_file_size_report_ignores_baseline_rows_outside_pr_scope() -> None:
     assert "| part-0.vortex | 1.0 |" not in report
 
 
+def test_file_size_report_omits_formats_the_pr_run_skipped() -> None:
+    compare = load_compare_module()
+
+    report = compare.format_file_size_report(
+        pd.DataFrame(
+            [
+                file_size_record_for("base-sha", 100, "tpch", "10", "vortex-file-compressed", "part-0.vortex"),
+                file_size_record_for("base-sha", 80, "tpch", "10", "vortex-compact", "part-0.vortex"),
+                file_size_record_for("base-sha", 5, "tpch", "10", "vortex-compact", "duckdb.db"),
+            ]
+        ),
+        pd.DataFrame(
+            [
+                file_size_record_for("pr-sha", 125, "tpch", "10", "vortex-file-compressed", "part-0.vortex"),
+            ]
+        ),
+    )
+
+    assert "<summary>File Size Changes (1 files changed, +25.0% overall, 1↑ 0↓)</summary>" in report
+    assert "vortex-compact" not in report
+    assert "-100.0%" not in report
+
+
 def test_capture_file_sizes_emits_shared_benchmark_rows(tmp_path: Path) -> None:
     data_dir = tmp_path / "data"
     format_dir = data_dir / "tpch" / "10" / "vortex-file-compressed"
diff --git a/vortex-btrblocks/tests/snapshots/golden__compact__list_of_int_runs.snap b/vortex-btrblocks/tests/snapshots/golden__compact__list_of_int_runs.snap
index 77a26802dd1..88274daf4b1 100644
--- a/vortex-btrblocks/tests/snapshots/golden__compact__list_of_int_runs.snap
+++ b/vortex-btrblocks/tests/snapshots/golden__compact__list_of_int_runs.snap
@@ -3,15 +3,11 @@ source: vortex-btrblocks/tests/golden.rs
 expression: rendered
 ---
 input: list(i32), len=4066, nbytes=81804
-root: vortex.list(list(i32), len=4066) nbytes=4748
+root: vortex.list(list(i32), len=4066) nbytes=4434
   metadata: 
   elements: vortex.zigzag(i32, len=16384) nbytes=2969
     metadata: 
     encoded: vortex.pco(u32, len=16384) nbytes=2969
       metadata: ptype: u32, nrows: 16384, slice: 0..16384
-  offsets: fastlanes.delta(u16, len=4067) nbytes=1779
-    metadata: offset: 0
-    bases: vortex.pco(u16, len=256) nbytes=243
-      metadata: ptype: u16, nrows: 256, slice: 0..256
-    deltas: fastlanes.bitpacked(u16, len=4096) nbytes=1536
-      metadata: bit_width: 3, offset: 0
+  offsets: vortex.pco(u16, len=4067) nbytes=1465
+    metadata: ptype: u16, nrows: 4067, slice: 0..4067