Heart rate recovery

Recently I have read how heart rate recovery is one of the best predictors of heart health. I have seen some contradictory research however on the criteria for a healthy recovery rate. The faster the heart rate drops the less likely someone is to have a heart attack. The minimum heart rate recovery per minute varies in the research from 12 up to 21. I am wondering what the accepted criteria is. My other question is whether heart rate recovery varies for one person depending on their exercise intensity. Personally I have a very good VO2 max but my heart rate recovery is poor 15-16bpm. What complicates my measurement is that I tend to exercise comfortably at a heart rate level that is very high for my age. I am 48 and my avg. BMP (use heart monitor) during running is typically around 155. So I am wondering whether my poor heart rate recovery is due to working near 91% of my maximum for somewhere around 30 minutes of running. I should probably just do some moderate exercise and see what my recovery rate is.
I seem to have such contradictory data: low resting heart rate, good to very good VO2max, but poor heart rate recovery numbers and a low average EF.