Getting Selected Rows Count Not Working After Using Iterator to Add 'selected' Class

I originally used the following code to select all my rows in the datatable:

$('#grid').DataTable().rows({ search: 'applied' }).select();

When using this, I immediately used the following to check if the count selected > 0. The count returned is correct.
$('#grid').DataTable().rows({ selected: true }).count()

I then wanted to use the iterator for all of the rows to be able to individually select or not select the row using the following code:

$('#grid').DataTable().rows().every(function (rowIdx, tableLoop, rowLoop) {
        $(this.node()).addClass('selected')
});

After selecting rows using the iterator, I check if the count selected > 0 by using the same call used above. The count returned is 0.
$('#grid').DataTable().rows({ selected: true }).count()

I checked the source for the table rows and the 'selected' class is properly assigned to each of the table rows (tr). I compared the source from both approaches and the resulting HTML is the same.

Any thoughts as to why the behavior would be different?

Thanks.
Tom