Visa Grant after signing Form 815

Me and my family are waiting for our 189 subclass visa grant since 133 days of lodging the application. VISA 189 Applied :6th Aug 2016. CO 1st Contact : 18th Aug 2016 for Spouse further Medical Tests. CO 2nd Contact : 22nd Nov 2016 for Spouse to sign Health Undertaking Form 815. All the responses made on the same day. No other communication so far and regarding the status as well. Please guide as we are now feeling depressed!!
I think after submission of 815 - it may take longer... as there is potentially some consultations with the doctor. Its pure my opinion, not based on factual knowledge.