diff --git a/src/modules/first-leg/components/InboundBillingPanel.test.mjs b/src/modules/first-leg/components/InboundBillingPanel.test.mjs
index 98edded..083ba22 100644
--- a/src/modules/first-leg/components/InboundBillingPanel.test.mjs
+++ b/src/modules/first-leg/components/InboundBillingPanel.test.mjs
@@ -19,7 +19,7 @@ test('shows the confirmed merchant inbound and fee fields without write actions'
     assert.match(source, new RegExp(label))
   }
   assert.match(source, /formatInboundMoney\(props\.data\.latestFee\.totalAmount/)
-  assert.match(source, /getRoundingModeLabel\(props\.data\.latestFee\.roundingMode\)/)
+  assert.match(source, /formatConversionPrecision\(/)
   assert.doesNotMatch(source, /确认费用|调整费用|发送费用|下载照片/)
   assert.doesNotMatch(source, /internalNotes|statusHistory|files/)
   assert.match(source, /latestFee\.ruleCode/)
diff --git a/src/modules/first-leg/components/InboundBillingPanel.vue b/src/modules/first-leg/components/InboundBillingPanel.vue
index 0b15be3..ec715c1 100644
--- a/src/modules/first-leg/components/InboundBillingPanel.vue
+++ b/src/modules/first-leg/components/InboundBillingPanel.vue
@@ -2,12 +2,12 @@
 import { Clock3, PackageCheck, RefreshCw, TriangleAlert } from '@lucide/vue'
 import type { MerchantInboundBilling } from '@/modules/first-leg/types/inboundBilling'
 import {
+  formatConversionPrecision,
   formatInboundDateTime,
   formatInboundMeasure,
   formatInboundMoney,
   formatInboundNumber,
   getChargeModeLabel,
-  getRoundingModeLabel,
   getTaxModeLabel,
 } from '@/modules/first-leg/utils/inboundBilling'
 
@@ -109,10 +109,11 @@ defineEmits<{
           <div><dt>计费方式</dt><dd>{{ getChargeModeLabel(props.data.latestFee.chargeMode) }} · {{ getTaxModeLabel(props.data.latestFee.taxMode) }}</dd></div>
           <div>
             <dt>换算与精度</dt>
-            <dd>
-              系数 {{ formatInboundNumber(props.data.latestFee.conversionFactor) }} ·
-              保留 {{ props.data.latestFee.roundingScale }} 位 {{ getRoundingModeLabel(props.data.latestFee.roundingMode) }}
-            </dd>
+            <dd>{{ formatConversionPrecision(
+              props.data.latestFee.conversionFactor,
+              props.data.latestFee.roundingScale,
+              props.data.latestFee.roundingMode,
+            ) }}</dd>
           </div>
           <div><dt>实际重量</dt><dd>{{ formatInboundMeasure(props.data.latestFee.actualWeightKg, 'kg') }}</dd></div>
           <div><dt>实际体积</dt><dd>{{ formatInboundMeasure(props.data.latestFee.actualVolumeCbm, 'm³') }}</dd></div>
diff --git a/src/modules/first-leg/types/inboundBilling.ts b/src/modules/first-leg/types/inboundBilling.ts
index e700078..68ffe25 100644
--- a/src/modules/first-leg/types/inboundBilling.ts
+++ b/src/modules/first-leg/types/inboundBilling.ts
@@ -79,9 +79,9 @@ export interface MerchantInboundFeeSnapshot {
   destinationCode: string
   taxMode: string
   chargeMode: 'KG' | 'CBM'
-  conversionFactor: number
-  roundingScale: number
-  roundingMode: string
+  conversionFactor: number | null
+  roundingScale: number | null
+  roundingMode: string | null
   actualWeightKg: number
   actualVolumeCbm: number
   convertedQuantity: number
diff --git a/src/modules/first-leg/utils/inboundBilling.test.mjs b/src/modules/first-leg/utils/inboundBilling.test.mjs
index bb093f5..fec95b4 100644
--- a/src/modules/first-leg/utils/inboundBilling.test.mjs
+++ b/src/modules/first-leg/utils/inboundBilling.test.mjs
@@ -16,5 +16,12 @@ test('translates backend rounding modes into customer-facing calculation labels'
   assert.match(source, /export function getRoundingModeLabel/)
   assert.match(source, /CEILING: '向上取整'/)
   assert.match(source, /HALF_UP: '四舍五入'/)
-  assert.match(source, /return labels\[value\] \|\| value \|\| '-'/)
+  assert.match(source, /return value \? labels\[value\] \|\| value : '-'/)
+})
+
+test('renders conversion metadata as one complete label or a single empty marker', () => {
+  assert.match(source, /export function formatConversionPrecision/)
+  assert.match(source, /roundingScale === null \|\| roundingScale === undefined/)
+  assert.match(source, /\|\| !roundingMode\) return '-'/)
+  assert.match(source, /`系数 \$\{formatInboundNumber\(conversionFactor\)\} · 保留 \$\{roundingScale\} 位 \$\{getRoundingModeLabel\(roundingMode\)\}`/)
 })
diff --git a/src/modules/first-leg/utils/inboundBilling.ts b/src/modules/first-leg/utils/inboundBilling.ts
index 842cd58..600fcad 100644
--- a/src/modules/first-leg/utils/inboundBilling.ts
+++ b/src/modules/first-leg/utils/inboundBilling.ts
@@ -46,7 +46,7 @@ export function getTaxModeLabel(value: string) {
   return value || '-'
 }
 
-export function getRoundingModeLabel(value: string) {
+export function getRoundingModeLabel(value: string | null | undefined) {
   const labels: Record<string, string> = {
     UP: '向上舍入',
     DOWN: '向下舍入',
@@ -56,5 +56,16 @@ export function getRoundingModeLabel(value: string) {
     HALF_DOWN: '五舍六入',
     HALF_EVEN: '银行家舍入',
   }
-  return labels[value] || value || '-'
+  return value ? labels[value] || value : '-'
+}
+
+export function formatConversionPrecision(
+  conversionFactor: number | null | undefined,
+  roundingScale: number | null | undefined,
+  roundingMode: string | null | undefined,
+) {
+  if (conversionFactor === null || conversionFactor === undefined
+    || roundingScale === null || roundingScale === undefined
+    || !roundingMode) return '-'
+  return `系数 ${formatInboundNumber(conversionFactor)} · 保留 ${roundingScale} 位 ${getRoundingModeLabel(roundingMode)}`
 }