Ground effect table (400)

I currently try to customize the flight dynamics of the PSS Dash-8 and have come across table 400 (Ground Effect) in the air file.Experimenting a bit, I saw that it controls airplane lift (i.e. with all values at 0 the plane stays grounded).Can someone briefly explain me what the x and y values are for and how a reasonable curve looks like?I tried to mimic the graph of the PMDG 737NG, and I have the impression that the landing behaviour of the Dash-8 got better.The PSS Dash-8 has the tendency to float a long way before settling onto the runway (i.e. with the original air file, during the flare at full flaps, when pulling the nose gently upwards to make the nose wheel rise, I need to be very cautious not to balloon and start climbing again).Andreas