Pivots are daily calculations, whatever time frame you are in is irrelevant, the daily pivot will be the same. You can use h+l+c/3 or h+l+c+today's Open/4. The pivot points are very important for SP floor traders, they work them out first thing including second resistance and support.
I only bother with main pivot and watch indices' reaction to it, it is like a light to moths. You can best study its effect on a 60 min chart.
Quick pivot calculations: