Size matters.
Making comparisons between K-Max and S-61's relative lifting abilities is surely a little irrelevant here, indeed between most helicopters. Each is designed for a purpose and while most can do most things they do them to varying degrees.
K-Max lifts, its lift capacity-basic weight ratio is very good and should be it was designed that way. A Lama has a very good ratio too but is much older! An S61 takes 23 pax in comfort, oh yeh and it lifts but the ratio is not so good.
If we are going to make comparisons it should be to prove a principle not a point.