Yes, I've used F-mods in the past (when my amps didn't have crossovers built-in, before I bought newer amps) and they worked quite well.

This is an interesting note about the lower limit for the EQ, and would explain why I was never able to make it satisfactorily work as a high pass filter. I wonder if this is a limitation of the DSP, or if it's a bug in the code?