diff --git a/src/aeros_simulation/router.py b/src/aeros_simulation/router.py
index 357c145..d6a7443 100644
--- a/src/aeros_simulation/router.py
+++ b/src/aeros_simulation/router.py
@@ -514,6 +514,7 @@ async def get_forecast_eaf(
 
     # 2. Determine Last Overhaul Date from Master Data
     oh_record = await _get_or_create_master_data(db_session, "Last Overhaul Date", 0)
+    next_oh = await _get_or_create_master_data(db_session, "Next Overhaul Date", 0)
     
     # If not set, use a fallback (e.g., start of current year)
     if not oh_record.value_string:
@@ -524,9 +525,11 @@ async def get_forecast_eaf(
     try:
         # Ensure oh_date is naive
         oh_date = datetime.fromisoformat(oh_date_str).replace(tzinfo=None)
+        next_oh_date = datetime.fromisoformat(next_oh.value_string).replace(tzinfo=None)
     except Exception:
         oh_date = datetime(now.year, 1, 1).replace(tzinfo=None)
 
+    oh_interval = hours_between(oh_date, next_oh_date)
     duration = 168 if time_range == "weekly" else 720
     end_date = now + timedelta(hours=duration)
     duration_simulation = hours_between(oh_date, end_date)
@@ -541,7 +544,8 @@ async def get_forecast_eaf(
         OffSet=0,
         SimSeed=1,
         SimNumRun=1,
-        IsDefault=False
+        IsDefault=False,
+        OverhaulInterval=oh_interval
     )
 
     # 6. Initialize Simulation in DB