diff --git a/quickwit/quickwit-control-plane/src/ingest/ingest_controller.rs b/quickwit/quickwit-control-plane/src/ingest/ingest_controller.rs
index 6cfbdcfc7ac..cc5f2b33fc5 100644
--- a/quickwit/quickwit-control-plane/src/ingest/ingest_controller.rs
+++ b/quickwit/quickwit-control-plane/src/ingest/ingest_controller.rs
@@ -676,10 +676,8 @@ impl IngestController {
         model: &mut ControlPlaneModel,
         progress: &Progress,
     ) -> MetastoreResult<()> {
-        const NUM_PERMITS: u64 = 1;
-
         if !model
-            .acquire_scaling_permits(&source_uid, ScalingMode::Up, NUM_PERMITS)
+            .acquire_scaling_permits(&source_uid, ScalingMode::Up)
             .unwrap_or(false)
         {
             return Ok(());
@@ -698,7 +696,7 @@ impl IngestController {
                 if successful_source_uids.is_empty() {
                     // We did not manage to create the shard.
                     // We can release our permit.
-                    model.release_scaling_permits(&source_uid, ScalingMode::Up, NUM_PERMITS);
+                    model.release_scaling_permits(&source_uid, ScalingMode::Up);
                     warn!(
                         index_uid=%source_uid.index_uid,
                         source_id=%source_uid.source_id,
@@ -722,7 +720,7 @@ impl IngestController {
                     source_id=%source_uid.source_id,
                     "scaling up number of shards to {new_num_open_shards} failed: {metastore_error:?}"
                 );
-                model.release_scaling_permits(&source_uid, ScalingMode::Up, NUM_PERMITS);
+                model.release_scaling_permits(&source_uid, ScalingMode::Up);
                 Err(metastore_error)
             }
         }
@@ -860,10 +858,12 @@ impl IngestController {
         model: &mut ControlPlaneModel,
         progress: &Progress,
     ) -> MetastoreResult<()> {
-        const NUM_PERMITS: u64 = 1;
+        if shard_stats.num_open_shards == 0 {
+            return Ok(());
+        }
 
         if !model
-            .acquire_scaling_permits(&source_uid, ScalingMode::Down, NUM_PERMITS)
+            .acquire_scaling_permits(&source_uid, ScalingMode::Down)
             .unwrap_or(false)
         {
             return Ok(());
@@ -876,12 +876,12 @@ impl IngestController {
             "scaling down number of shards to {new_num_open_shards}"
         );
         let Some((leader_id, shard_id)) = find_scale_down_candidate(&source_uid, model) else {
-            model.release_scaling_permits(&source_uid, ScalingMode::Down, NUM_PERMITS);
+            model.release_scaling_permits(&source_uid, ScalingMode::Down);
             return Ok(());
         };
         info!("scaling down shard {shard_id} from {leader_id}");
         let Some(ingester) = self.ingester_pool.get(&leader_id) else {
-            model.release_scaling_permits(&source_uid, ScalingMode::Down, NUM_PERMITS);
+            model.release_scaling_permits(&source_uid, ScalingMode::Down);
             return Ok(());
         };
         let shard_pkeys = vec![ShardPKey {
@@ -896,7 +896,7 @@ impl IngestController {
             .await
         {
             warn!("failed to scale down number of shards: {error}");
-            model.release_scaling_permits(&source_uid, ScalingMode::Down, NUM_PERMITS);
+            model.release_scaling_permits(&source_uid, ScalingMode::Down);
             return Ok(());
         }
         model.close_shards(&source_uid, &[shard_id]);
diff --git a/quickwit/quickwit-control-plane/src/model/mod.rs b/quickwit/quickwit-control-plane/src/model/mod.rs
index ca314233f6a..d4e02f67c2c 100644
--- a/quickwit/quickwit-control-plane/src/model/mod.rs
+++ b/quickwit/quickwit-control-plane/src/model/mod.rs
@@ -378,10 +378,9 @@ impl ControlPlaneModel {
         &mut self,
         source_uid: &SourceUid,
         scaling_mode: ScalingMode,
-        num_permits: u64,
     ) -> Option<bool> {
         self.shard_table
-            .acquire_scaling_permits(source_uid, scaling_mode, num_permits)
+            .acquire_scaling_permits(source_uid, scaling_mode)
     }
 
     pub fn drain_scaling_permits(&mut self, source_uid: &SourceUid, scaling_mode: ScalingMode) {
@@ -389,14 +388,9 @@ impl ControlPlaneModel {
             .drain_scaling_permits(source_uid, scaling_mode)
     }
 
-    pub fn release_scaling_permits(
-        &mut self,
-        source_uid: &SourceUid,
-        scaling_mode: ScalingMode,
-        num_permits: u64,
-    ) {
+    pub fn release_scaling_permits(&mut self, source_uid: &SourceUid, scaling_mode: ScalingMode) {
         self.shard_table
-            .release_scaling_permits(source_uid, scaling_mode, num_permits)
+            .release_scaling_permits(source_uid, scaling_mode)
     }
 }
 
diff --git a/quickwit/quickwit-control-plane/src/model/shard_table.rs b/quickwit/quickwit-control-plane/src/model/shard_table.rs
index 29c579cddcd..b2581adcbad 100644
--- a/quickwit/quickwit-control-plane/src/model/shard_table.rs
+++ b/quickwit/quickwit-control-plane/src/model/shard_table.rs
@@ -544,14 +544,13 @@ impl ShardTable {
         &mut self,
         source_uid: &SourceUid,
         scaling_mode: ScalingMode,
-        num_permits: u64,
     ) -> Option<bool> {
         let table_entry = self.table_entries.get_mut(source_uid)?;
         let scaling_rate_limiter = match scaling_mode {
             ScalingMode::Up => &mut table_entry.scaling_up_rate_limiter,
             ScalingMode::Down => &mut table_entry.scaling_down_rate_limiter,
         };
-        Some(scaling_rate_limiter.acquire(num_permits))
+        Some(scaling_rate_limiter.acquire(1))
     }
 
     pub fn drain_scaling_permits(&mut self, source_uid: &SourceUid, scaling_mode: ScalingMode) {
@@ -564,18 +563,13 @@ impl ShardTable {
         }
     }
 
-    pub fn release_scaling_permits(
-        &mut self,
-        source_uid: &SourceUid,
-        scaling_mode: ScalingMode,
-        num_permits: u64,
-    ) {
+    pub fn release_scaling_permits(&mut self, source_uid: &SourceUid, scaling_mode: ScalingMode) {
         if let Some(table_entry) = self.table_entries.get_mut(source_uid) {
             let scaling_rate_limiter = match scaling_mode {
                 ScalingMode::Up => &mut table_entry.scaling_up_rate_limiter,
                 ScalingMode::Down => &mut table_entry.scaling_down_rate_limiter,
             };
-            scaling_rate_limiter.release(num_permits);
+            scaling_rate_limiter.release(1);
         }
     }
 }