I know what your saying and looked at that link, and i still can't get my head around how when its a + offset reducing the offset from 50 to 30 pushes the wheel farther out, i'm looking at it in this way, you have a wheel fitted to a car, and with a + offset totalling 50, made up of a 30mm offset built into the wheel and a 20mm offset made up by a spacer! if you remove the spacer which way does the wheel move?? now my logic says inwards!
but i am seeing a + offset as the hub mounting face projecting beyond the centre line towards the inside of the wheel closer to the suspension therefore moving the wheel outwards towards the arch, and - offset as the hub mounting face receding from the centre line towards the outside of the wheel, so as offset is reduced from + to - the wheel moves further inwards! now to me that make perfect sense! but other info presented seem to point to the opposite???