diff --git a/lez/wallet-ffi/src/wallet.rs b/lez/wallet-ffi/src/wallet.rs
index e9c12f63..b2846912 100644
--- a/lez/wallet-ffi/src/wallet.rs
+++ b/lez/wallet-ffi/src/wallet.rs
@@ -154,8 +154,8 @@ pub unsafe extern "C" fn wallet_ffi_create_new(
 /// This loads a wallet that was previously created with `wallet_ffi_create_new()`.
 ///
 /// # Parameters
-/// - `handle` - Valid wallet handle
 /// - `config_path`: Path to the wallet configuration file (JSON)
+/// - `storage_path`: Path to the wallet storage (JSON)
 /// - `statistics_path`: Path to the wallet statistics file (JSON)
 ///
 /// # Returns
@@ -164,7 +164,6 @@ pub unsafe extern "C" fn wallet_ffi_create_new(
 ///
 /// # Safety
 /// All string parameters must be valid null-terminated UTF-8 strings.
-/// `handle` must be a valid wallet handle from `wallet_ffi_create_new` or `wallet_ffi_open`.
 #[no_mangle]
 pub unsafe extern "C" fn wallet_ffi_open(
     config_path: *const c_char,
diff --git a/lez/wallet-ffi/wallet_ffi.h b/lez/wallet-ffi/wallet_ffi.h
index 4a795c23..bbd7da1f 100644
--- a/lez/wallet-ffi/wallet_ffi.h
+++ b/lez/wallet-ffi/wallet_ffi.h
@@ -1633,8 +1633,8 @@ struct FfiCreateWalletOutput wallet_ffi_create_new(const char *config_path,
  * This loads a wallet that was previously created with `wallet_ffi_create_new()`.
  *
  * # Parameters
- * - `handle` - Valid wallet handle
  * - `config_path`: Path to the wallet configuration file (JSON)
+ * - `storage_path`: Path to the wallet storage (JSON)
  * - `statistics_path`: Path to the wallet statistics file (JSON)
  *
  * # Returns
@@ -1643,7 +1643,6 @@ struct FfiCreateWalletOutput wallet_ffi_create_new(const char *config_path,
  *
  * # Safety
  * All string parameters must be valid null-terminated UTF-8 strings.
- * `handle` must be a valid wallet handle from `wallet_ffi_create_new` or `wallet_ffi_open`.
  */
 struct WalletHandle *wallet_ffi_open(const char *config_path,
                                      const char *storage_path,
diff --git a/lez/wallet/src/config.rs b/lez/wallet/src/config.rs
index cb09f5c2..ede71073 100644
--- a/lez/wallet/src/config.rs
+++ b/lez/wallet/src/config.rs
@@ -7,6 +7,8 @@ use log::warn;
 use serde::{Deserialize, Serialize};
 use url::Url;
 
+const DEFAULT_CALLIBRATION_LIMIT: usize = 100;
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct SequencerConnectionData {
     /// Connection data of all known sequencers.
@@ -49,6 +51,7 @@ pub struct WalletConfig {
     /// Max amount of blocks to poll in one request.
     pub seq_block_poll_max_amount: u64,
     /// Limit number of sequencer polls during calibration, should not be zero
+    #[serde(default = "default_calibration_limit")]
     pub calibration_limit: usize,
 }
 
@@ -63,7 +66,7 @@ impl Default for WalletConfig {
             seq_tx_poll_max_blocks: 5,
             seq_poll_max_retries: 5,
             seq_block_poll_max_amount: 100,
-            calibration_limit: 100,
+            calibration_limit: DEFAULT_CALLIBRATION_LIMIT,
         }
     }
 }
@@ -151,3 +154,7 @@ impl WalletConfig {
         }
     }
 }
+
+const fn default_calibration_limit() -> usize {
+    DEFAULT_CALLIBRATION_LIMIT
+}
diff --git a/lez/wallet/src/multi_client.rs b/lez/wallet/src/multi_client.rs
index 7a8968fa..499cf7a1 100644
--- a/lez/wallet/src/multi_client.rs
+++ b/lez/wallet/src/multi_client.rs
@@ -213,17 +213,11 @@ impl MultiSequencerClient {
         resp
     }
 
+    /// Update statistics of a leader, clear statist updates log.
     pub async fn update_statistics(&self, leader_statistic: &mut Statistics) {
-        {
-            let statistic_updates = self.statistic_updates.read().await;
-            leader_statistic.apply_updates(statistic_updates.as_ref());
-        }
-
-        // Clear updates
-        {
-            let mut statistic_updates = self.statistic_updates.write().await;
-            statistic_updates.clear();
-        }
+        let mut statistic_updates = self.statistic_updates.write().await;
+        leader_statistic.apply_updates(statistic_updates.as_ref());
+        statistic_updates.clear();
     }
 }
 
@@ -368,10 +362,8 @@ pub fn choose_leader(
     client_list: &HashMap<Url, SequencerClient>,
     statistics: &HashMap<Url, Statistics>,
 ) -> Option<(Url, SequencerClient)> {
-    let mut client_vec = vec![];
-
     // Sort out all unmetered clients
-    client_vec = client_list
+    let mut client_vec: Vec<_> = client_list
         .keys()
         .filter(|item| statistics.contains_key(*item))
         .collect();
diff --git a/test_fixtures/src/config.rs b/test_fixtures/src/config.rs
index b35f7f16..449308eb 100644
--- a/test_fixtures/src/config.rs
+++ b/test_fixtures/src/config.rs
@@ -203,7 +203,7 @@ pub fn wallet_config(sequencer_addr: SocketAddr) -> Result<WalletConfig> {
         seq_tx_poll_max_blocks: 15,
         seq_poll_max_retries: 10,
         seq_block_poll_max_amount: 100,
-        calibration_limit: 1,
+        calibration_limit: 5,
     })
 }