My husband and I just bought the RO 125 FEQ , we are having a hard time getting a fine finish. Right now we are working with walnut and trying to get it ready for oil.... we are sanding with 400 grit sandpaper, using very little to no pressure and we keep getting swirl/scuff marks. I am not talking about the ones made from the sandpaper.... these scuff marks from the edge of the pad..... we are using the semi soft pad that came with the sander a...... do we need to use the softer sanding pad? WE have tried all the different speeds and have it in the fine sanding mode.... it also tends to walk/chatter across the wood......... We are using a different brand of sandpaper, not a festool brand.....