diff --git a/db/routines/R__088_fn_forecast_pv_slots_range_canonical_ab.sql b/db/routines/R__088_fn_forecast_pv_slots_range_canonical_ab.sql
index d777ef7..c07f2a2 100644
--- a/db/routines/R__088_fn_forecast_pv_slots_range_canonical_ab.sql
+++ b/db/routines/R__088_fn_forecast_pv_slots_range_canonical_ab.sql
@@ -31,7 +31,21 @@ set work_mem = '64MB'
 as $fn$
 declare
   v_result jsonb;
+  v_rolling_factor numeric;
 begin
+  -- Rolling faktor JEDNOU do proměnné: jako inlinovaná CTE (single-ref) se
+  -- fn_pv_forecast_correction_factor vyhodnocovala per výstupní řádek
+  -- (~300× ≈ 570k buffers / ~4 s — skutečná příčina pomalosti, ne plan cache).
+  v_rolling_factor := coalesce(
+    (ems.fn_pv_forecast_correction_factor(
+      p_site_id,
+      (p_now - (p_factor_window_h::text || ' hours')::interval)::timestamptz,
+      p_now,
+      p_factor_min_clamp,
+      p_factor_max_clamp
+    )->>'correction_factor')::numeric,
+    1.0
+  );
   -- PG 18 cachuje plán SQL/plpgsql statementů s parametry → generický plán
   -- (4.5–9 s / 600k buffers); force_custom_plan na funkci nepomohl. Execute
   -- s literály vynutí čerstvý plán dle skutečných hodnot: 0.4 s / 34k buffers.
@@ -70,20 +84,6 @@ begin
     from slot_spine s
     cross join tz t
   ),
-  factor_raw as (
-    select ems.fn_pv_forecast_correction_factor(
-      %1$s,
-      (%4$L::timestamptz - (%9$s::text || ' hours')::interval)::timestamptz,
-      %4$L::timestamptz,
-      %10$s,
-      %11$s
-    ) as j
-  ),
-  factor as (
-    select
-      coalesce((j->>'correction_factor')::numeric, 1.0::numeric) as rolling_factor
-    from factor_raw
-  ),
   profile as (
     select ems.fn_pv_forecast_delta_profile_cached(
       %1$s,
@@ -194,18 +194,17 @@ begin
       ab.pv_b_forecast_raw_w,
       ab.pv_a_forecast_delta_w,
       ab.pv_b_forecast_delta_w,
-      f.rolling_factor,
+      %13$s::numeric as rolling_factor,
       case
         when ab.interval_start < b.now_slot then 1.0::numeric
-        when %12$s <= 0 then f.rolling_factor
+        when %12$s <= 0 then %13$s::numeric
         else
           case
             when ((extract(epoch from (ab.interval_start - b.now_slot)) / 900)::int) >= %12$s then 1.0::numeric
-            else (1.0::numeric + (f.rolling_factor - 1.0::numeric) * (1.0::numeric - ((extract(epoch from (ab.interval_start - b.now_slot)) / 900)::numeric / %12$s::numeric)))
+            else (1.0::numeric + (%13$s::numeric - 1.0::numeric) * (1.0::numeric - ((extract(epoch from (ab.interval_start - b.now_slot)) / 900)::numeric / %12$s::numeric)))
           end
       end as rolling_effective_factor
     from fc_ab ab
-    cross join factor f
     cross join bounds b
   )
   select coalesce(
@@ -242,7 +241,8 @@ $q$,
     p_factor_window_h,
     p_factor_min_clamp,
     p_factor_max_clamp,
-    p_decay_slots
+    p_decay_slots,
+    v_rolling_factor
   ) into v_result;
   return coalesce(v_result, '[]'::jsonb);
 end;