Lactate Threshold

Hi,
Last year I did the 24 week mountaineering program for my solo Aconcagua trip. Now I’m doing the 20 week big mountain for the Pikes Peak marathon in September.
I did my lactate threshold test the other day, I got an avg HR of 181. I did a 30min test uphill for 1100 feet of elevation gain, 6,200 feet to 7,300 feet, the trail ended. My top of zone 2 is 160 and I am a 31 year old male.
My pace was really slow, 12:20 min/mile, because of the steepness of the run. Should I try it again and aim for a higher pace? I’m pretty sure I could maintain a higher HR. or should I be happy with the 181 average HR since its above the 10% difference?