diff --git a/mvp/b2c/src/budget/compute.ts b/mvp/b2c/src/budget/compute.ts
index f729df3..756166f 100644
--- a/mvp/b2c/src/budget/compute.ts
+++ b/mvp/b2c/src/budget/compute.ts
@@ -81,10 +81,12 @@ export function computeBudget(
   }));
 
   const subtotal = partidas.reduce((s, p) => s + p.importe, 0);
-  const factorZona = (inputs.provincia && config.factorZona[inputs.provincia]) || 1;
+  const factorZona = config.factorZona[inputs.provincia ?? ''] ?? 1;
   const total = Math.round(subtotal * factorZona);
 
-  const hasExact = Object.keys(inputs.materialSelections).length > 0;
+  const hasExact = (Object.values(inputs.materialSelections) as string[]).some(
+    (id) => catalog.some((c) => c.id === id),
+  );
   const hasM2 = inputs.m2Suelo != null && inputs.m2Suelo > 0;
   let confianza: BudgetResult['confianza'];
   let band: number;
diff --git a/mvp/b2c/tests/budget/compute.test.ts b/mvp/b2c/tests/budget/compute.test.ts
index 34ea6aa..601c9d9 100644
--- a/mvp/b2c/tests/budget/compute.test.ts
+++ b/mvp/b2c/tests/budget/compute.test.ts
@@ -76,4 +76,29 @@ describe('computeBudget', () => {
     const r = computeBudget(inputs({}), config, sinPintura);
     expect(r.avisos.some((a) => a.includes('pintura'))).toBe(true);
   });
+
+  it('usa factor zona 1 para provincia desconocida', () => {
+    const r = computeBudget(inputs({ provincia: 'Cuenca' }), config, catalog);
+    expect(r.factorZona).toBe(1);
+    expect(r.total).toBe(536000); // subtotal sin factor
+  });
+
+  it('respeta un factor zona explícito de 0', () => {
+    const configZero: PricingConfig = { ...config, factorZona: { ...config.factorZona, Madrid: 0 } };
+    const r = computeBudget(inputs({ provincia: 'Madrid' }), configZero, catalog);
+    expect(r.factorZona).toBe(0);
+    expect(r.total).toBe(0);
+  });
+
+  it('no sube la confianza si la selección apunta a un material inexistente', () => {
+    const r = computeBudget(inputs({ materialSelections: { suelo: 'no-existe' } }), config, catalog);
+    expect(r.confianza).toBe('media'); // tiene m² pero la selección no resuelve -> no es alta
+  });
+
+  it('omite carpintería y no rompe para tipos sin mobiliario (salón)', () => {
+    const r = computeBudget(inputs({ tipoReforma: 'salon' }), config, catalog);
+    const byKey = Object.fromEntries(r.partidas.map((p) => [p.key, p.importe]));
+    expect(byKey.carpinteria).toBeUndefined();
+    expect(r.total).toBeGreaterThan(0);
+  });
 });