diff --git a/simnode/src/client/parachain.rs b/simnode/src/client/parachain.rs
index 75190a9..53ec453 100644
--- a/simnode/src/client/parachain.rs
+++ b/simnode/src/client/parachain.rs
@@ -39,15 +39,14 @@ use sc_service::{
 use sc_transaction_pool::FullPool;
 use sc_transaction_pool_api::{OffchainTransactionPoolFactory, TransactionPool};
 use simnode_runtime_api::CreateTransactionApi;
-use sp_api::{ApiExt, ConstructRuntimeApi, Core};
+use sp_api::{ApiExt, ConstructRuntimeApi, Core, ProvideRuntimeApi};
 use sp_block_builder::BlockBuilder;
 use sp_blockchain::HeaderBackend;
 use sp_consensus::SelectChain;
-use sp_core::{crypto::AccountId32, Bytes};
+use sp_consensus_aura::AuraApi;
+use sp_core::{crypto::AccountId32, traits::SpawnEssentialNamed, Bytes};
 use sp_runtime::traits::{Block as BlockT, Header};
 use sp_transaction_pool::runtime_api::TaggedTransactionQueue;
-
-use sp_core::traits::SpawnEssentialNamed;
 use std::sync::Arc;
 
 /// Parachain handler implementation for Simnode RPC API.
@@ -213,8 +212,14 @@ where
 		other: (block_import, mut telemetry, _),
 	} = components;
 
-	let parachain_inherent_provider =
-		Arc::new(Mutex::new(ParachainSproofInherentProvider::<C>::new(client.clone())));
+	let slot_duration = client
+		.runtime_api()
+		.slot_duration(client.info().best_hash)
+		.map_err(|err| sc_service::Error::Application(Box::new(err)))?;
+
+	let parachain_inherent_provider = Arc::new(Mutex::new(
+		ParachainSproofInherentProvider::<C>::new(client.clone(), slot_duration.as_millis()),
+	));
 
 	let net_config = sc_network::config::FullNetworkConfiguration::new(&config.network);
 	let (network, system_rpc_tx, tx_handler_controller, _network_starter, sync_service) = {
diff --git a/simnode/src/sproof.rs b/simnode/src/sproof.rs
index 1256aab..72ab6a3 100644
--- a/simnode/src/sproof.rs
+++ b/simnode/src/sproof.rs
@@ -37,6 +37,8 @@ pub struct ParachainSproofInherentProvider<T: ChainInfo> {
 	client: Arc<FullClientFor<T>>,
 	// sproof builder
 	sproof_builder: Option<RelayStateSproofBuilder>,
+	// slot duration for the node
+	slot_duration: u64,
 	// phantom type
 	_phantom: PhantomData<T>,
 }
@@ -51,8 +53,13 @@ where
 	<<T::Block as Block>::Header as Header>::Number: AsPrimitive<u32>,
 {
 	/// Construct a new sproof-er
-	pub fn new(client: Arc<FullClientFor<T>>) -> Self {
-		ParachainSproofInherentProvider { client, sproof_builder: None, _phantom: PhantomData }
+	pub fn new(client: Arc<FullClientFor<T>>, slot_duration: u64) -> Self {
+		ParachainSproofInherentProvider {
+			client,
+			slot_duration,
+			sproof_builder: None,
+			_phantom: PhantomData,
+		}
 	}
 
 	/// updates the sproof to a new state
@@ -71,8 +78,13 @@ where
 		sproof.para_id = with_state::<T, _>(self.client.clone(), None, || {
 			parachain_info::Pallet::<T::Runtime>::parachain_id()
 		});
-		// relay chain is twice as fast the parachain
-		sproof.current_slot = ((slot * 2) + 1).into();
+		sproof.current_slot = if self.slot_duration == 12_000 {
+			// relay chain is twice as fast the parachain
+			((slot * 2) + 1).into()
+		} else {
+			// async backing is enabled
+			slot.into()
+		};
 		sproof.host_config.validation_upgrade_delay = 2;
 		sproof.host_config.max_code_size = 15 * 1024 * 1024;
 		sproof.included_para_head =