Hm when quickly looking at your code and the code from John I see that he uses:
batchChanges.push( that.oModel.createBatchOperation("Contacts", "POST", contactEntry1) );
and you use
oModel.createBatchOperation('/CREATE_DVR',POST,batchChanges,null,function(response){...
That seems not correct. Also you are never sending your request? John does:
that.oModel.submitBatch(function(data) { ...
and I don't see submitBatch at your code?!
Maybe you have a look at openSAP - next steps in software development on HANA - week 4 - unit 6 - deep insert & batch requests.
https://open.sap.com/courses/hana2/items/42yDjpxcjSPSzz4JFCvA3H