Subgrid method getTotalRecordCount returning -1 after adding a record to the subgrid

I am getting a subgrid's recordcount inside of its onload function like so:

Xrm.Page.getControl('AllAddresses').addOnLoad(function () {

var totalCount = Xrm.Page.getControl('AllAddresses').getGrid().getTotalRecordCount();

console.log(totalCount); 

});

If I add a record to the subgrid this function is triggered again, but this time totalCount is -1. 

This should be the actual count of the records in the subgrid. If I reload the entire page it will log the correct count