I always use FT1 Polar Heart Rate Monitor, so I know it's right. I have done the time trial test during my long ride, short ride and indoor cycling. I always sit when climbing steep hills which that's were I'm comfortable. The 20min Indoor cycling time trial test using exercise bikes was way different. I follow your instructions to pace 20min evenly with max effort. The result was much lower average HR and lower max HR. The only way I can hit zone 4-5 is to spin really fast in the level 12-15 on a exercise bike and if I choose a much heavier tension to pace, my HR drops. The outdoor test with my Mtb always gives me a high average and max. One thing is that even I hit 176-182 max HR, I can say I'm ok and HR drops back to zone 2 in few minutes. I just don't think writing 147 average HR in your chart matches the way my HR Zone is. My warm-up spin easy goes to Zone 2 and everything else is always much higher. Maybe It's just me or is my time trail wrong. I always monitor my HR with all my rides plus I already muted the zone limit warning coz it beeps all the time.Hehehehe
Thanks
Dazs