Is the amount recovered per day ( ≒ 0.1428… )?
Or is it 15%?

In an unofficial Japanese wiki, I tried to show how to estimate hit points after n days by applying the sum of a geometric progression formulas.
However, as shown in the attached image, the official wiki and the explanation in the game showed different numbers as common ratios.
So I am confused.
Because official wiki said 15%, a calculation of 15% is adopted now at the said informal wiki tentatively, if it's not too much trouble, It would be happy if developer may tell me the correct value.

Really?
Supposing you said, I would rather know the error range or coefficient.