Subtract / Remove Weight Paint in hair particles density without Changing Scale and position

hello everyone, i need to help for my problem with particles vertex group density. i make a vertex group and i painting in weight paint for particles density, but next i want to erase some area, but all hair particles going to changing with scale and position. i try in particles edit for cut the hair particles, that's working but some things still change, but not as much as changes when using subtract in weight paint. some body can help me please.... thank you