I, if you find out I also would be interested in making this change? P

Please elaborate further, If you are referring to Alerts, you can set a single buzz or double buzz alarm to notify you if your heart rate goes above or below the limit that you choose. The full range for the alert can be from 0 to 255. so you can set your alert at 170 with an upper limit if you want the alert to buzz when you reach or pass the 170 heart beat limit. you can also set the select the radio button to lower limit and the alert will buzz if you go below 170. however, if you are referring to your heart rate zones, That is done on your running platform such as Strava, Runalyze, Final surge ect.

You just slide along the heart rate bar.

If what you are saying, changing heart rate max so zones would represent that, I love to see that.