Ajisai's perfect compatibility with Renako despite the fact they don't end up together is proof that Renako is a beautifully flawed character who will ultimately find happiness because she genuinely cares for others who are kind yet- drunk rambling :aquadrink:
The harem knows where Renako is at all times. It knows this because it knows where she isn't. By subtracting where she is from where she isn't, or where she isn't from where she is (whichever is greater), it obtains a difference or deviation.