diff --git a/src/objective-c/tests/InteropTests.m b/src/objective-c/tests/InteropTests.m
index 5584246ad94..d964f53e8e2 100644
--- a/src/objective-c/tests/InteropTests.m
+++ b/src/objective-c/tests/InteropTests.m
@@ -90,6 +90,9 @@
   return nil;
 }
 
+// This number indicates how many bytes of overhead does Protocol Buffers encoding add onto the
+// message. The number varies as different message.proto is used on different servers. The actual
+// number for each interop server is overridden in corresponding derived test classes.
 - (int32_t)encodingOverhead {
   return 0;
 }
@@ -169,8 +172,6 @@
   [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
-#ifndef GRPC_COMPILE_WITH_CRONET
-// TODO (mxyan): Fix this test
 - (void)testResponsesOverMaxSizeFailWithActionableMessage {
   XCTAssertNotNil(self.class.host);
   __weak XCTestExpectation *expectation = [self expectationWithDescription:@"ResponseOverMaxSize"];
@@ -191,7 +192,6 @@
 
   [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
-#endif
 
 - (void)testResponsesOver4MBAreAcceptedIfOptedIn {
   XCTAssertNotNil(self.class.host);
@@ -327,8 +327,6 @@
   [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
-#ifndef GRPC_COMPILE_WITH_CRONET
-// TODO(makdharma@): Fix this test
 - (void)testEmptyStreamRPC {
   XCTAssertNotNil(self.class.host);
   __weak XCTestExpectation *expectation = [self expectationWithDescription:@"EmptyStream"];
@@ -342,7 +340,6 @@
   }];
   [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
-#endif
 
 - (void)testCancelAfterBeginRPC {
   XCTAssertNotNil(self.class.host);
diff --git a/src/objective-c/tests/InteropTestsLocalCleartext.m b/src/objective-c/tests/InteropTestsLocalCleartext.m
index b41210f50f8..49876608087 100644
--- a/src/objective-c/tests/InteropTestsLocalCleartext.m
+++ b/src/objective-c/tests/InteropTestsLocalCleartext.m
@@ -37,6 +37,10 @@
 
 static NSString * const kLocalCleartextHost = @"localhost:5050";
 
+// The Protocol Buffers encoding overhead of local interop server. Acquired
+// by experiment. Adjust this when server's proto file changes.
+static int32_t kLocalInteropServerOverhead = 10;
+
 /** Tests in InteropTests.m, sending the RPCs to a local cleartext server. */
 @interface InteropTestsLocalCleartext : InteropTests
 @end
@@ -48,7 +52,7 @@ static NSString * const kLocalCleartextHost = @"localhost:5050";
 }
 
 - (int32_t)encodingOverhead {
-  return 10; // bytes
+  return kLocalInteropServerOverhead; // bytes
 }
 
 - (void)setUp {
diff --git a/src/objective-c/tests/InteropTestsLocalSSL.m b/src/objective-c/tests/InteropTestsLocalSSL.m
index 1479c5896c3..934d500abc0 100644
--- a/src/objective-c/tests/InteropTestsLocalSSL.m
+++ b/src/objective-c/tests/InteropTestsLocalSSL.m
@@ -37,6 +37,10 @@
 
 static NSString * const kLocalSSLHost = @"localhost:5051";
 
+// The Protocol Buffers encoding overhead of local interop server. Acquired
+// by experiment. Adjust this when server's proto file changes.
+static int32_t kLocalInteropServerOverhead = 10;
+
 /** Tests in InteropTests.m, sending the RPCs to a local SSL server. */
 @interface InteropTestsLocalSSL : InteropTests
 @end
@@ -48,7 +52,7 @@ static NSString * const kLocalSSLHost = @"localhost:5051";
 }
 
 - (int32_t)encodingOverhead {
-  return 10; // bytes
+  return kLocalInteropServerOverhead; // bytes
 }
 
 - (void)setUp {
diff --git a/src/objective-c/tests/InteropTestsRemote.m b/src/objective-c/tests/InteropTestsRemote.m
index 70f84753bb6..9fb30aa43d0 100644
--- a/src/objective-c/tests/InteropTestsRemote.m
+++ b/src/objective-c/tests/InteropTestsRemote.m
@@ -37,6 +37,10 @@
 
 static NSString * const kRemoteSSLHost = @"grpc-test.sandbox.googleapis.com";
 
+// The Protocol Buffers encoding overhead of remote interop server. Acquired
+// by experiment. Adjust this when server's proto file changes.
+static int32_t kRemoteInteropServerOverhead = 12;
+
 /** Tests in InteropTests.m, sending the RPCs to a remote SSL server. */
 @interface InteropTestsRemote : InteropTests
 @end
@@ -48,7 +52,7 @@ static NSString * const kRemoteSSLHost = @"grpc-test.sandbox.googleapis.com";
 }
 
 - (int32_t)encodingOverhead {
-  return 12; // bytes
+  return kRemoteInteropServerOverhead; // bytes
 }
 
 @end
diff --git a/src/objective-c/tests/InteropTestsRemoteWithCronet/InteropTestsRemoteWithCronet.m b/src/objective-c/tests/InteropTestsRemoteWithCronet/InteropTestsRemoteWithCronet.m
index fab8ad8d25f..005bac0a0d4 100644
--- a/src/objective-c/tests/InteropTestsRemoteWithCronet/InteropTestsRemoteWithCronet.m
+++ b/src/objective-c/tests/InteropTestsRemoteWithCronet/InteropTestsRemoteWithCronet.m
@@ -37,6 +37,10 @@
 
 static NSString * const kRemoteSSLHost = @"grpc-test.sandbox.googleapis.com";
 
+// The Protocol Buffers encoding overhead of remote interop server. Acquired
+// by experiment. Adjust this when server's proto file changes.
+static int32_t kRemoteInteropServerOverhead = 12;
+
 /** Tests in InteropTests.m, sending the RPCs to a remote SSL server. */
 @interface InteropTestsRemoteWithCronet : InteropTests
 @end
@@ -47,4 +51,8 @@ static NSString * const kRemoteSSLHost = @"grpc-test.sandbox.googleapis.com";
   return kRemoteSSLHost;
 }
 
+- (int32_t)encodingOverhead {
+  return kRemoteInteropServerOverhead; // bytes
+}
+
 @end