diff --git a/net/dcsctp/common/sequence_numbers.h b/net/dcsctp/common/sequence_numbers.h
index 4f318c3..52b638b 100644
--- a/net/dcsctp/common/sequence_numbers.h
+++ b/net/dcsctp/common/sequence_numbers.h
@@ -121,19 +121,26 @@
 
   // Increments the value.
   void Increment() { ++value_; }
+
+  // Returns the next value relative to this sequence number.
   UnwrappedSequenceNumber<WrappedType> next_value() const {
     return UnwrappedSequenceNumber<WrappedType>(value_ + 1);
   }
 
-  // Adds a delta to the current value.
-  UnwrappedSequenceNumber<WrappedType> AddTo(int delta) const {
-    return UnwrappedSequenceNumber<WrappedType>(value_ + delta);
+  // Returns a new sequence number based on `value`, and adding `delta` (which
+  // may be negative).
+  static UnwrappedSequenceNumber<WrappedType> AddTo(
+      UnwrappedSequenceNumber<WrappedType> value,
+      int delta) {
+    return UnwrappedSequenceNumber<WrappedType>(value.value_ + delta);
   }
 
-  // Compares the difference between two sequence numbers.
-  typename WrappedType::UnderlyingType Difference(
-      UnwrappedSequenceNumber<WrappedType> other) const {
-    return value_ - other.value_;
+  // Returns the absolute difference between `lhs` and `rhs`.
+  static typename WrappedType::UnderlyingType Difference(
+      UnwrappedSequenceNumber<WrappedType> lhs,
+      UnwrappedSequenceNumber<WrappedType> rhs) {
+    return (lhs.value_ > rhs.value_) ? (lhs.value_ - rhs.value_)
+                                     : (rhs.value_ - lhs.value_);
   }
 
  private:
diff --git a/net/dcsctp/common/sequence_numbers_test.cc b/net/dcsctp/common/sequence_numbers_test.cc
index d1d1959..f5fa788 100644
--- a/net/dcsctp/common/sequence_numbers_test.cc
+++ b/net/dcsctp/common/sequence_numbers_test.cc
@@ -32,9 +32,9 @@
   EXPECT_LT(s1, s3);
   EXPECT_LT(s2, s3);
 
-  EXPECT_EQ(s1.Difference(s0), 1);
-  EXPECT_EQ(s2.Difference(s0), 2);
-  EXPECT_EQ(s3.Difference(s0), 3);
+  EXPECT_EQ(TestSequence::Difference(s1, s0), 1);
+  EXPECT_EQ(TestSequence::Difference(s2, s0), 2);
+  EXPECT_EQ(TestSequence::Difference(s3, s0), 3);
 
   EXPECT_GT(s1, s0);
   EXPECT_GT(s2, s0);
@@ -50,7 +50,7 @@
   s2.Increment();
   EXPECT_EQ(s2, s3);
 
-  EXPECT_EQ(s0.AddTo(2), s3);
+  EXPECT_EQ(TestSequence::AddTo(s0, 2), s3);
 }
 
 TEST(SequenceNumbersTest, MidValueUnwrapping) {
@@ -68,9 +68,9 @@
   EXPECT_LT(s1, s3);
   EXPECT_LT(s2, s3);
 
-  EXPECT_EQ(s1.Difference(s0), 1);
-  EXPECT_EQ(s2.Difference(s0), 2);
-  EXPECT_EQ(s3.Difference(s0), 3);
+  EXPECT_EQ(TestSequence::Difference(s1, s0), 1);
+  EXPECT_EQ(TestSequence::Difference(s2, s0), 2);
+  EXPECT_EQ(TestSequence::Difference(s3, s0), 3);
 
   EXPECT_GT(s1, s0);
   EXPECT_GT(s2, s0);
@@ -86,7 +86,7 @@
   s2.Increment();
   EXPECT_EQ(s2, s3);
 
-  EXPECT_EQ(s0.AddTo(2), s3);
+  EXPECT_EQ(TestSequence::AddTo(s0, 2), s3);
 }
 
 TEST(SequenceNumbersTest, WrappedUnwrapping) {
@@ -104,9 +104,9 @@
   EXPECT_LT(s1, s3);
   EXPECT_LT(s2, s3);
 
-  EXPECT_EQ(s1.Difference(s0), 1);
-  EXPECT_EQ(s2.Difference(s0), 2);
-  EXPECT_EQ(s3.Difference(s0), 3);
+  EXPECT_EQ(TestSequence::Difference(s1, s0), 1);
+  EXPECT_EQ(TestSequence::Difference(s2, s0), 2);
+  EXPECT_EQ(TestSequence::Difference(s3, s0), 3);
 
   EXPECT_GT(s1, s0);
   EXPECT_GT(s2, s0);
@@ -122,7 +122,7 @@
   s2.Increment();
   EXPECT_EQ(s2, s3);
 
-  EXPECT_EQ(s0.AddTo(2), s3);
+  EXPECT_EQ(TestSequence::AddTo(s0, 2), s3);
 }
 
 TEST(SequenceNumbersTest, WrapAroundAFewTimes) {
@@ -183,5 +183,20 @@
   }
 }
 
+TEST(SequenceNumbersTest, DifferenceIsAbsolute) {
+  TestSequence::Unwrapper unwrapper;
+
+  TestSequence this_value = unwrapper.Unwrap(Wrapped(10));
+  TestSequence other_value = TestSequence::AddTo(this_value, 100);
+
+  EXPECT_EQ(TestSequence::Difference(this_value, other_value), 100);
+  EXPECT_EQ(TestSequence::Difference(other_value, this_value), 100);
+
+  TestSequence minus_value = TestSequence::AddTo(this_value, -100);
+
+  EXPECT_EQ(TestSequence::Difference(this_value, minus_value), 100);
+  EXPECT_EQ(TestSequence::Difference(minus_value, this_value), 100);
+}
+
 }  // namespace
 }  // namespace dcsctp
diff --git a/net/dcsctp/rx/data_tracker.cc b/net/dcsctp/rx/data_tracker.cc
index 9e5cbe2..b95cb44 100644
--- a/net/dcsctp/rx/data_tracker.cc
+++ b/net/dcsctp/rx/data_tracker.cc
@@ -179,9 +179,10 @@
 
   auto flush = [&]() {
     if (first_tsn_in_block.has_value()) {
-      int start_diff =
-          first_tsn_in_block->Difference(last_cumulative_acked_tsn_);
-      int end_diff = last_tsn_in_block->Difference(last_cumulative_acked_tsn_);
+      int start_diff = UnwrappedTSN::Difference(*first_tsn_in_block,
+                                                last_cumulative_acked_tsn_);
+      int end_diff = UnwrappedTSN::Difference(*last_tsn_in_block,
+                                              last_cumulative_acked_tsn_);
       gap_ack_blocks.emplace_back(static_cast<uint16_t>(start_diff),
                                   static_cast<uint16_t>(end_diff));
       first_tsn_in_block = absl::nullopt;
diff --git a/net/dcsctp/rx/traditional_reassembly_streams.cc b/net/dcsctp/rx/traditional_reassembly_streams.cc
index caa97d2..7cec115 100644
--- a/net/dcsctp/rx/traditional_reassembly_streams.cc
+++ b/net/dcsctp/rx/traditional_reassembly_streams.cc
@@ -172,7 +172,8 @@
     return 0;
   }
 
-  uint32_t tsn_diff = chunks.rbegin()->first.Difference(chunks.begin()->first);
+  uint32_t tsn_diff =
+      UnwrappedTSN::Difference(chunks.rbegin()->first, chunks.begin()->first);
   if (tsn_diff != chunks.size() - 1) {
     return 0;
   }