diff --git a/lib/pricecaster.js b/lib/pricecaster.js
index ed8abc3b..41fc8ce9 100644
--- a/lib/pricecaster.js
+++ b/lib/pricecaster.js
@@ -8,7 +8,7 @@ const approvalProgramFilename = 'teal/pricekeeper.teal'
 const clearProgramFilename = 'teal/clearstate.teal'
 
 class PricecasterLib {
-  constructor (algodClient, ownerAddr = undefined) {
+  constructor(algodClient, ownerAddr = undefined) {
     this.algodClient = algodClient
     this.ownerAddr = ownerAddr
     this.minFee = 1000
@@ -139,8 +139,8 @@ class PricecasterLib {
     this.createApp = async function (sender, validatorAddr, symbol, signCallback) {
       const localInts = 0
       const localBytes = 0
-      const globalInts = 2
-      const globalBytes = 4
+      const globalInts = 6
+      const globalBytes = 2
 
       // declare onComplete as NoOp
       const onComplete = algosdk.OnApplicationComplete.NoOpOC
@@ -204,6 +204,51 @@ class PricecasterLib {
       return txId
     }
 
+    /**
+     * Internal function.
+     * Call application specifying args and accounts.  Do it in a group of dummy TXs for maximizing computations.
+     * @param  {String} sender caller address
+     * @param  {Array} appArgs array of arguments to pass to application call
+     * @param  {Array} appAccounts array of accounts to pass to application call
+     * @param  {Function} signCallback callback with prototype signCallback(sender, tx) used to sign transactions
+     * @param  {number} dummyTxCount the number of dummyTx to submit, with the real call last.
+     * @return {String} transaction id of the transaction
+     */
+    this.callAppInDummyGroup = async function (sender, appArgs, appAccounts, signCallback, dummyTxCount) {
+      // get node suggested parameters
+      const params = await this.algodClient.getTransactionParams().do()
+
+      params.fee = this.minFee
+      params.flatFee = true
+
+      console.log(appArgs)
+
+      const txns = []
+      const enc = new TextEncoder()
+      for (let i = 0; i < dummyTxCount; ++i) {
+        txns.push(algosdk.makeApplicationNoOpTxn(sender,
+          params,
+          this.appId,
+          undefined, undefined, undefined, undefined,
+          enc.encode(`dummy_TX_${i}`)))
+      }
+      const appTx = algosdk.makeApplicationNoOpTxn(sender, params, this.appId, appArgs)
+      txns.push(appTx)
+      algosdk.assignGroupID(txns)
+      const txId = appTx.txID().toString()
+
+      // Sign the transactions
+      const signedTxns = []
+      for (const tx of txns) {
+        signedTxns.push(signCallback(sender, tx))
+      }
+
+      // Submit the transaction
+      await this.algodClient.sendRawTransaction(signedTxns).do()
+
+      return txId
+    }
+
     /**
          * ClearState sender. Remove all the sender associated local data.
          * @param  {String} sender account to ClearState
@@ -305,29 +350,34 @@ class PricecasterLib {
      * Creates a message with price data for the PriceKeeper contract
      * @param {BigInt} nonce Sequence number
      * @param {String} symbol Symbol, must match appid support, 16-char UTF long
-     * @param {number} price Price, expected in 64-bit floating-point format.
-     * @param {number} confidence Confidence, expected in 64-bit floating-point format.
+     * @param {BigInt} price Aggregated price
+     * @param {BigInt} confidence Confidence
+     * @param {BigInt} exp Exponent (positive)
+     * @param {BigInt} slot Valid-slot of price aggregation
      * @param {Uint8Array} sk Signing key.
      * @returns A base64-encoded message.
      */
-    this.createMessage = function (nonce, symbol, price, confidence, sk) {
-      const buf = Buffer.alloc(130)
+    this.createMessage = function (nonce, symbol, price, exp, confidence, slot, sk) {
+      const buf = Buffer.alloc(146)
       buf.write('PRICEDATA', 0)
       buf.writeInt8(1, 9)
       buf.writeBigUInt64BE(BigInt(this.appId), 10)
       buf.writeBigUInt64BE(nonce, 18)
       buf.write(symbol, 26)
-      buf.writeDoubleBE(price, 42)
-      buf.writeDoubleBE(confidence, 50)
-      buf.writeBigUInt64BE(BigInt(Math.floor(Date.now() / 1000)), 58)
+      buf.writeBigUInt64BE(price, 42)
+      buf.writeBigUInt64BE(exp, 50)
+      buf.writeBigUInt64BE(confidence, 58)
+      buf.writeBigUInt64BE(slot, 66)
+      buf.writeBigUInt64BE(BigInt(Math.floor(Date.now() / 1000)), 74)
 
-      const digestu8 = Buffer.from(sha512_256(buf.slice(0, 65)), 'hex')
-      console.log(digestu8.toString('base64'))
-      console.log(this.approvalProgramHash)
+      const digestu8 = Buffer.from(sha512_256(buf.slice(0, 82)), 'hex')
+      // console.log(digestu8.toString('base64'))
+      // console.log(this.approvalProgramHash)
       const signature = Buffer.from(algosdk.tealSign(sk, digestu8, this.approvalProgramHash))
-      console.log(Buffer.from(signature).toString('base64'))
-      signature.copy(buf, 66)
-      return buf.toString('base64')
+      // console.log(Buffer.from(signature).toString('base64'))
+      signature.copy(buf, 82)
+      // console.log(buf.toString('base64'))
+      return buf
     }
 
     /**
@@ -336,8 +386,10 @@ class PricecasterLib {
      * @param {*} msgb64 Base64-encoded message.
      * @returns Transaction identifier (txid)
      */
-    this.submitMessage = async function (sender, msgb64, signCallback) {
-      return await this.callApp(sender, [new Uint8Array(msgb64)], [], signCallback)
+    this.submitMessage = async function (sender, msgBuffer, signCallback) {
+      const appArgs = []
+      appArgs.push(new Uint8Array(msgBuffer))
+      return await this.callAppInDummyGroup(sender, appArgs, [], signCallback, 3)
     }
   }
 }