External Mode simulation on host with ert.tlc fails

I'm running Matlab&Simulink r2017b on x64 PC with Microsoft Visual Studio v15 toolchain, trying to learn Simulink External Mode, following the article below:

External Mode Simulation with TCP/IP or Serial Communication - MATLAB & Simulink

I did created the example model in the article, and configured exactly the same as told (system target file is 'grt.tlc' in that case). It works fine.

However, when I only change the system target file to 'ert.tlc', it does not work correctly (simulation outputs 0 for each signal, no matter what A or B is)

To elaborate more:

• I run the external apps with the flags '-tf inf -w', in both cases it honors the flags and waits for Simulink to connect and start simulation.
• I start simulation after connecting the target. In 'grt.tlc' case, it outputs signals correctly to the scopes, updates tunable parameter values correctly. When i switch to 'ert.tlc', it only outputs 0 for signals.

I checked all configurations to be same in the article, even tried to remove any parameter references from the model and made them constant, still no achievement.

What would be the cause of that difference between 'ert.tlc' and 'grt.tlc' when it comes to External Mode? Is there a fundamental error of mine, when working with 'ert.tlc'?