diff --git a/services/hwfit/fit.py b/services/hwfit/fit.py
index fb0e006..6dd3b89 100644
--- a/services/hwfit/fit.py
+++ b/services/hwfit/fit.py
@@ -280,10 +280,14 @@ def _native_quant(model):
         return "FP8"
     if "gptq" in text:
         m = re.search(r"(?:gptq|int|w)(?:[-_]?)(\d{1,2})(?:bit)?", text)
-        return f"GPTQ-{m.group(1)}bit" if m else "GPTQ"
+        # Canonical catalog label is "GPTQ-Int4"/"GPTQ-Int8" (see models.py
+        # QUANT_BPP / QUANT_QUALITY_PENALTY keys); "GPTQ-4bit" misses both
+        # maps, so BPP and the quality penalty silently fall to defaults.
+        return f"GPTQ-Int{m.group(1)}" if m else "GPTQ-Int4"
     if "awq" in text:
         m = re.search(r"(?:awq|int|w)(?:[-_]?)(\d{1,2})(?:bit)?", text)
-        return f"AWQ-{m.group(1)}bit" if m else "AWQ"
+        # Catalog keys are "AWQ-4bit"/"AWQ-8bit"; bare "AWQ" misses the maps.
+        return f"AWQ-{m.group(1)}bit" if m else "AWQ-4bit"
     if "mlx" in text:
         m = re.search(r"mlx[-_]?(\d{1,2})bit", text)
         return f"mlx-{m.group(1)}bit" if m else native_quant
diff --git a/tests/test_hwfit_native_quant_labels.py b/tests/test_hwfit_native_quant_labels.py
new file mode 100644
index 0000000..c73f979
--- /dev/null
+++ b/tests/test_hwfit_native_quant_labels.py
@@ -0,0 +1,42 @@
+"""_native_quant must emit canonical quant labels that key the cost maps.
+
+services/hwfit/models.py keys QUANT_BPP and QUANT_QUALITY_PENALTY on
+"GPTQ-Int4"/"GPTQ-Int8" and "AWQ-4bit"/"AWQ-8bit". _native_quant returned
+"GPTQ-4bit" (and bare "AWQ" when no digit), which miss both maps, so a
+pre-quantized GPTQ/AWQ model fell back to the default BPP (0.58 instead of
+0.50) and a zero quality penalty, over-estimating VRAM and inflating the
+score. The label is also shown in the UI and disagreed with the catalog.
+"""
+from services.hwfit.fit import _native_quant
+from services.hwfit.models import QUANT_BPP, QUANT_QUALITY_PENALTY
+
+
+def test_gptq_int4_label_is_canonical():
+    label = _native_quant({"name": "Qwen2.5-32B-Instruct-GPTQ-Int4"})
+    assert label == "GPTQ-Int4"
+    assert label in QUANT_BPP and label in QUANT_QUALITY_PENALTY
+
+
+def test_gptq_int8_label_is_canonical():
+    label = _native_quant({"name": "x-GPTQ-Int8"})
+    assert label == "GPTQ-Int8"
+    assert label in QUANT_BPP and label in QUANT_QUALITY_PENALTY
+
+
+def test_awq_no_digit_falls_back_to_canonical():
+    label = _native_quant({"name": "SomeModel-AWQ"})
+    assert label == "AWQ-4bit"
+    assert label in QUANT_BPP and label in QUANT_QUALITY_PENALTY
+
+
+def test_awq_with_digit_is_canonical():
+    label = _native_quant({"name": "x-AWQ-8bit"})
+    assert label == "AWQ-8bit"
+    assert label in QUANT_BPP and label in QUANT_QUALITY_PENALTY
+
+
+def test_gptq_fallback_label_is_in_maps():
+    # GPTQ mentioned with no parseable bit-width
+    label = _native_quant({"name": "model-gptq", "format": ""})
+    assert label == "GPTQ-Int4"
+    assert label in QUANT_BPP and label in QUANT_QUALITY_PENALTY