yeah, it supports mtr (for one filter only) but not pattr. Use number boxes for the parameters as Stefan suggested, this gives more "knowing" control over your stuff. Working with multiple filters would also be possible, though since you’re changing an index number (dicrete steps) these wouldn’t interpolate like a frequency setting on a single filter would (though I haven’t tried it, I don’t see how it could). Splitting up into different filtergraphs would work better for a multiple-filter case.
Mtr and pattr for filtergraph makes for some pretty powerful stuff!