Indoor walk vs outdoor walk inaccuracy

The way Apple Watch averages all outdoor walks to come up with an average for indoor walks doesn't work. When I walk indoors on a treadmill I tend to walk much faster and up a 6-8% grade typically. But I rarely get my heart rate high enough to have it qualify as a workout. Can I override the watch's totals after an indoor walk to get credit for the work I am putting in? The treadmill totals are def more accurate.