Mat FX Oil Paint - any way to remove warping?

Hi guys,
I'm loving the MatFX Oil Paint filter, its been a big help on a recent job so I'm hoping to use it again on another one. However I need a bit more fine grain control. In this case I need to completely remove all warping from the brush strokes. We're going for straight square brush strokes and this is almost what we need but I cannot seem to remove the warping from it no matter what I try. You can see warp intensity is set to 0 (on everything, Hightlights, Midtones, Shadows).

Anyone have any ideas?
Cheers