Its april 2016 yet no healer stat weights???

[Granyala]

But like you say, a 1% increase on 1000 heal is less than on a 3000 heal but is 1% regardless.

That's not how the math works.

1% is not a constant value.
1% of 1K = 10
1% of 3K = 30

The question would be: 72 DET = +1%
From what? Current performance? Some hidden base value?

Agreed on the average.
Testing with <100 stat is rather useless because Statistics will likely swallow up most differences (unless you heal 100K times).