New heart rate monitor

Hi all,

I ve just started to run again after a couple of years so I thought I would treat myself to a new heart rate monitor. I went for the polar rs400, a bit flash but i thought go for it, Any way, I did a tredmill test and got my max hr and got my resting hr so i could work out my working heart rate zones. my max is 189 and my resting is 54, I'm training at 60%-70% at the moment which I've worked out to be 135-148. BUT when I use the watches heart rate zones it has me at 113-135 for 60%-70%. Am i doing something completly stupid here or is my new all singing all dancing watch up the wall?

Thanks Nigel.