Unfortunately the figures published by Sound Pro's are only correct if your recorder's input impedance is 10 Kohms. If your input has another impedance, let's call it X, you would have to multiply the listed roll offs by 10/X to get the correct roll off. They really are not being honest in not explaining this.
This makes things pretty complicated. It's better to do roll offs in post anyway because there is no danger of rolling off more bass than you need to.