Hi,
The code changes in that post are already in the 3.5.0 so you should already have them.
So if you still have the issue even though you're using the 3.5.0, then there is only one thing to check, and that is the important note of the step 1 of that post.
So check if you have the file templates/YOUR_TEMPLATE/html/com_hikashop/category/listing.php ( the override of the view file category/listing.php ). If you do, rename it or apply the patch of the step1 to it, and that should definitely fix the problem.