On the Department of Justice website they have a pdf file by Professor Carol Rogerson and Professor Rollie Thompson. In this they talk about spousal support being in the range from 37.5 to 50% and then mention that this works out to a maximum of 48%. Does anyone know why 50 becomes 48? Is there some hidden cost I'm not aware of?
Note the addition of an equalization of net income “cap” to the formula for amount in the Final Version. (FV, 7.4.1). This “cap” applies to long marriages of 25 years or more, where the range is 37.5 to 50 per cent of the gross income difference. The “cap” implements the idea that the recipient should never receive an amount of spousal support that will leave him or her with more than 50 per cent of the spouses’ net disposable income or monthly cash flow. The software programs can calculate this net income cap with precision and will present the cap as the upper limit of the range. For those without software, or without more precise net income calculations, the net income cap can be estimated crudely by hand, at 48 per cent of the gross income difference. This “48 per cent” method is a second-best, but adequate, alternative.

Thanks for your help!