Tazocin in HD patients

I have a question about Tazocin. I am taking a look at our procedure for administering Tazocin in HD patients, we currently are giving 2.25g iv q8h with a 0.75g top up dose post dialysis. I have heard it through the grapevine that there are a couple centers out there just giving 2.25g q6h and leaving it at that...any body doing that...and if you are is there any reference for it, or is it more convenience (and for lack of mistakes of admin!!). I can buy that! Thanks everyone!