diff --git a/lib/bcoin/mempool.js b/lib/bcoin/mempool.js
index f52df67b..efa14849 100644
--- a/lib/bcoin/mempool.js
+++ b/lib/bcoin/mempool.js
@@ -642,11 +642,19 @@ Mempool.prototype.addTX = function addTX(tx, callback, force) {
       0));
   }
 
-  if (!tx.isSane(ret))
-    return callback(new VerifyError(tx, 'invalid', ret.reason, ret.score));
+  if (!tx.isSane(ret)) {
+    return callback(new VerifyError(tx,
+      'invalid',
+      ret.reason,
+      ret.score));
+  }
 
-  if (tx.isCoinbase())
-    return callback(new VerifyError(tx, 'invalid', 'coinbase', 100));
+  if (tx.isCoinbase()) {
+    return callback(new VerifyError(tx,
+      'invalid',
+      'coinbase',
+      100));
+  }
 
   if (this.requireStandard) {
     if (!tx.isStandard(flags, ret))
@@ -661,16 +669,24 @@ Mempool.prototype.addTX = function addTX(tx, callback, force) {
   }
 
   if (!this.chain.segwitActive && !this.prematureWitness) {
-    if (tx.hasWitness())
-      return callback(new VerifyError(tx, 'nonstandard', 'no-witness-yet', 0));
+    if (tx.hasWitness()) {
+      return callback(new VerifyError(tx,
+        'nonstandard',
+        'no-witness-yet',
+        0));
+    }
   }
 
   this.chain.checkFinal(this.chain.tip, tx, lockFlags, function(err, isFinal) {
     if (err)
       return callback(err);
 
-    if (!isFinal)
-      return callback(new VerifyError(tx, 'nonstandard', 'non-final', 0));
+    if (!isFinal) {
+      return callback(new VerifyError(tx,
+        'nonstandard',
+        'non-final',
+        0));
+    }
 
     self.has(hash, function(err, exists) {
       if (err)
@@ -885,10 +901,7 @@ Mempool.prototype.getMinRate = function getMinRate() {
     }
   }
 
-  if (this.minFeeRate > this.minReasonableFee)
-    return this.minFeeRate;
-
-  return this.minReasonableFee;
+  return Math.max(this.minFeeRate, this.minReasonableFee);
 };
 
 /**
@@ -1853,7 +1866,7 @@ MempoolEntry.prototype.getPriority = function getPriority(height) {
   var heightDelta = height - this.height;
   var modSize = this.tx.getModifiedSize(this.size);
   var deltaPriority = heightDelta * this.chainValue / modSize;
-  var result = this.priority * deltaPriority;
+  var result = this.priority + deltaPriority;
   if (result < 0)
     result = 0;
   return result;
@@ -1907,10 +1920,11 @@ function mallocUsage(alloc) {
   return ((alloc + 15) >>> 3) << 3;
 }
 
-Mempool.MempoolEntry = MempoolEntry;
-
 /*
  * Expose
  */
 
-module.exports = Mempool;
+exports = Mempool;
+exports.MempoolEntry = MempoolEntry;
+
+module.exports = exports;