diff --git a/src/App.tsx b/src/App.tsx
index c1b84f5..d533676 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -2201,14 +2201,18 @@ export default function App() {
     return hasNonEmptyRuleValue(nodeLike?.startDateRule) || hasNonEmptyRuleValue(nodeLike?.dateAdjustmentRule);
   };
 
-  // 内部工作时间计算函数
-  const addInternalBusinessTime = (startDate: Date, businessDays: number, weekendDays: number[] = [], excludedDates: string[] = []): Date => {
+  const addBusinessTimeWithWindow = (
+    startDate: Date,
+    businessDays: number,
+    weekendDays: number[] = [],
+    excludedDates: string[] = [],
+    startHour: number,
+    endHour: number
+  ): Date => {
     const result = new Date(startDate);
     if (!businessDays || businessDays === 0) return result;
     const isNegative = businessDays < 0;
     const absDays = Math.abs(businessDays);
-    
-    // 处理整数天（仅计入工作日）
     const wholeDays = Math.floor(absDays);
     let processedDays = 0;
     while (processedDays < wholeDays) {
@@ -2217,110 +2221,65 @@ export default function App() {
         processedDays++;
       }
     }
-    
-    // 处理小数部分（按9小时工作制）
     const fractionalDays = absDays - wholeDays;
     if (fractionalDays > 0) {
-      const workingHours = fractionalDays * 9; // 内部按9小时工作制
-      let currentHour = result.getHours();
-      let currentMinute = result.getMinutes();
-      
+      const workMinutes = Math.round(fractionalDays * (endHour - startHour) * 60);
+      const startMinutes = startHour * 60;
+      const endMinutes = endHour * 60;
+      const currentMinutes = result.getHours() * 60 + result.getMinutes();
       if (!isNegative) {
-        // 正向：确保在工作时间内开始
-        if (currentHour < 9) {
-          currentHour = 9;
-          currentMinute = 0;
-        } else if (currentHour >= 18) {
-          // 跳到下一个工作日的9:00
+        let cursor = currentMinutes;
+        if (cursor < startMinutes) {
+          cursor = startMinutes;
+        } else if (cursor >= endMinutes) {
           result.setDate(result.getDate() + 1);
           while (!isBusinessDay(result, weekendDays, excludedDates)) {
             result.setDate(result.getDate() + 1);
           }
-          currentHour = 9;
-          currentMinute = 0;
+          cursor = startMinutes;
         }
-        
-        const totalMinutes = currentHour * 60 + currentMinute + workingHours * 60;
-        const finalHour = Math.floor(totalMinutes / 60);
-        const finalMinute = totalMinutes % 60;
-        
-        if (finalHour >= 18) {
-          const overflowHours = finalHour - 18;
-          const overflowMinutes = finalMinute;
+        let total = cursor + workMinutes;
+        while (total >= endMinutes) {
+          const overflow = total - endMinutes;
           result.setDate(result.getDate() + 1);
           while (!isBusinessDay(result, weekendDays, excludedDates)) {
             result.setDate(result.getDate() + 1);
           }
-          result.setHours(9 + overflowHours, overflowMinutes, 0, 0);
-        } else {
-          result.setHours(finalHour, finalMinute, 0, 0);
+          total = startMinutes + overflow;
         }
+        result.setHours(Math.floor(total / 60), total % 60, 0, 0);
       } else {
-        // 负向：从当前时间向前回退工作小时，规范到工作时间窗口
-        if (currentHour > 18) {
-          // 当天超过18:00，先归位到18:00
-          result.setHours(18, 0, 0, 0);
-          currentHour = 18;
-          currentMinute = 0;
-        } else if (currentHour < 9) {
-          // 早于9:00，跳到前一个工作日的18:00
+        let cursor = currentMinutes;
+        if (cursor > endMinutes) {
+          cursor = endMinutes;
+        } else if (cursor <= startMinutes) {
           result.setDate(result.getDate() - 1);
           while (!isBusinessDay(result, weekendDays, excludedDates)) {
             result.setDate(result.getDate() - 1);
           }
-          result.setHours(18, 0, 0, 0);
-          currentHour = 18;
-          currentMinute = 0;
+          cursor = endMinutes;
         }
-        
-        const totalMinutes = currentHour * 60 + currentMinute - workingHours * 60;
-        if (totalMinutes >= 9 * 60) {
-          const finalHour = Math.floor(totalMinutes / 60);
-          const finalMinute = totalMinutes % 60;
-          result.setHours(finalHour, finalMinute, 0, 0);
-        } else {
-          // 需要跨到前一个工作日，计算欠缺分钟数
-          let deficit = 9 * 60 - totalMinutes; // 需要从前一工作日的18:00再退回的分钟数
-          // 跳到前一个工作日
+        let total = cursor - workMinutes;
+        while (total < startMinutes) {
+          const deficit = startMinutes - total;
           result.setDate(result.getDate() - 1);
           while (!isBusinessDay(result, weekendDays, excludedDates)) {
             result.setDate(result.getDate() - 1);
           }
-          // 从18:00开始退 deficit 分钟
-          result.setHours(18, 0, 0, 0);
-          result.setMinutes(result.getMinutes() - deficit);
+          total = endMinutes - deficit;
         }
+        result.setHours(Math.floor(total / 60), total % 60, 0, 0);
       }
     }
-    
     return result;
   };
 
-  // 添加工作日 - 使用表格配置的休息日与节点自定义跳过日期
+  const addInternalBusinessTime = (startDate: Date, businessDays: number, weekendDays: number[] = [], excludedDates: string[] = []): Date => {
+    return addBusinessTimeWithWindow(startDate, businessDays, weekendDays, excludedDates, 9, 18);
+  };
+
   const addBusinessDaysWithHolidays = (startDate: Date, businessDays: number, weekendDays: number[] = [], excludedDates: string[] = []): Date => {
-    const result = new Date(startDate);
-    if (!businessDays || businessDays === 0) return result;
-    const isNegative = businessDays < 0;
-    const absDays = Math.abs(businessDays);
-    let processedDays = 0;
-    
-    // 先处理整数工作日
-    const wholeDays = Math.floor(absDays);
-    while (processedDays < wholeDays) {
-      result.setDate(result.getDate() + (isNegative ? -1 : 1));
-      if (isBusinessDay(result, weekendDays, excludedDates)) {
-        processedDays++;
-      }
-    }
-    
-    // 再处理小数部分（按24小时制）
-    const fractionalDays = absDays - wholeDays;
-    if (fractionalDays > 0) {
-      const hours = fractionalDays * 24;
-      result.setHours(result.getHours() + (isNegative ? -hours : hours));
-    }
-    
-    return result;
+    return addBusinessTimeWithWindow(startDate, businessDays, weekendDays, excludedDates, 0, 24);
   };