Hikvision substream issue - do I need to enable other ports?

For performance reason I am trying to downgrade the camera quality on some home computers - and I thought I would use the sub-stream.

Within the iVMS 4200 software, I changed the stream type to sub-stream (Device management, double click on each camera) but that doesn't seem to change the stream in the main view window.

I verified the lower quality via the camera web interface - main stream vs sub stream in live view - so that is working.

Do I need to enable other ports for sub-stream? Or any other thoughts what I am missing?

Thanks!

Just close and open again the stream, on the "main view".

Thanks MindTwist - Tried that.

And tried to relaunch iVMS, reboot, synch with camera, etc - but the quality seems to be still at 5mp quality.

Attached is the sub-stream quality specs which I think would be very noticeable difference vs the main stream 5mp quality.

Any other suggestions?