diff --git a/libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.cpp b/libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.cpp
index 4b401ab6..72dfc857 100644
--- a/libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.cpp
+++ b/libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.cpp
@@ -95,19 +95,22 @@ SessionContext* CryptoEngine::FindSession(SessionId sid) {
   return nullptr;
 }
 
-int64_t CryptoEngine::OnlineTime() {
+int64_t CryptoEngine::MonotonicTime() {
   // Use the monotonic clock for times that don't have to be stable across
   // device boots.
-  int64_t now = wvcdm::Clock().GetCurrentTime();
+  int64_t now =
+      wvcdm::Clock().GetCurrentTime() + offline_time_info_.rollback_offset;
   static int64_t then = now;
-  if (now < then) now = then;
+  if (now < then) {
+    offline_time_info_.rollback_offset += then - now;
+    now = then;
+  }
   then = now;
   return now;
 }
 
-int64_t CryptoEngine::RollbackCorrectedOfflineTime() {
-  // Add any time offsets in the past to the current time.
-  int64_t current_time = OnlineTime() + offline_time_info_.rollback_offset;
+int64_t CryptoEngine::SystemTime() {
+  const int64_t current_time = MonotonicTime();
   // Write time info to disk if kTimeInfoUpdateWindowInSeconds has elapsed since
   // last write.
   if (current_time - offline_time_info_.previous_time >
@@ -125,9 +128,9 @@ std::string CryptoEngine::GetUsageTimeFileFullPath() const {
   // TODO(fredgc, jfore): Address how this property is presented to the ref.
   // For now, the file path is empty.
   /*if (!wvcdm::Properties::GetDeviceFilesBasePath(wvcdm::kSecurityLevelL3,
-                                                   &file_path)) {
-      LOGE("RollbackCorrectedOfflineTime: Unable to get base path");
-  }*/
+    &file_path)) {
+    LOGE("Unable to get base path");
+    }*/
   return file_path + kStoredUsageTimeFileName;
 }
 
@@ -148,8 +151,7 @@ bool CryptoEngine::LoadOfflineTimeInfo(const std::string& file_path) {
     std::unique_ptr<wvcdm::File> file =
         file_system->Open(file_path, wvcdm::FileSystem::kReadOnly);
     if (!file) {
-      LOGE("RollbackCorrectedOfflineTime: File open failed: %s",
-           file_path.c_str());
+      LOGE("File open failed: %s", file_path.c_str());
       return false;
     }
     // Load time info from previous call.
@@ -164,7 +166,7 @@ bool CryptoEngine::LoadOfflineTimeInfo(const std::string& file_path) {
 
     // Detect offline time rollback after loading from disk.
     // Add any time offsets in the past to the current time.
-    int64_t current_time = OnlineTime() + offline_time_info_.rollback_offset;
+    int64_t current_time = MonotonicTime();
     if (offline_time_info_.previous_time > current_time) {
       // Current time is earlier than the previously saved time. Time has been
       // rolled back. Update the rollback offset.
@@ -184,7 +186,7 @@ bool CryptoEngine::SaveOfflineTimeInfo(const std::string& file_path) {
   // earlier offline rollback, the rollback offset will be updated in
   // LoadOfflineTimeInfo().  It guarantees that the current time to be saved
   // will never go back.
-  int64_t current_time = OnlineTime() + offline_time_info_.rollback_offset;
+  const int64_t current_time = MonotonicTime();
   // The new previous_time will either stay the same or move forward.
   if (current_time > offline_time_info_.previous_time)
     offline_time_info_.previous_time = current_time;
@@ -213,8 +215,7 @@ bool CryptoEngine::SaveOfflineTimeInfo(const std::string& file_path) {
   file = file_system->Open(
       file_path, wvcdm::FileSystem::kCreate | wvcdm::FileSystem::kTruncate);
   if (!file) {
-    LOGE("RollbackCorrectedOfflineTime: File open failed: %s",
-         file_path.c_str());
+    LOGE("File open failed: %s", file_path.c_str());
     return false;
   }
   file->Write(reinterpret_cast<char*>(&encrypted_buffer[0]), sizeof(TimeInfo));
diff --git a/libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.h b/libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.h
index dd39e16f..552f59a7 100644
--- a/libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.h
+++ b/libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.h
@@ -104,8 +104,7 @@ class CryptoEngine {
   }
 
   // The OEMCrypto system time. Prevents time rollback.
-  // TODO(b/145836634): Combine RollbackCorrectedOfflineTime with OnlineTime().
-  int64_t SystemTime() { return RollbackCorrectedOfflineTime(); }
+  int64_t SystemTime();
 
   // Verify that this nonce does not collide with another nonce in any session.
   virtual bool NonceCollision(uint32_t nonce);
@@ -224,11 +223,8 @@ class CryptoEngine {
   }
 
  protected:
-  // System clock, measuring time in seconds.
-  int64_t OnlineTime();
-
-  // System clock with antirollback protection, measuring time in seconds.
-  int64_t RollbackCorrectedOfflineTime();
+  // System clock, measuring time in seconds, including anti-rollback offset.
+  int64_t MonotonicTime();
 
   bool LoadOfflineTimeInfo(const std::string& file_path);
   bool SaveOfflineTimeInfo(const std::string& file_path);