There is two dots of deflection in each direction for both the localiser and the glideslope indicators. The displacment that is diplayed on either of these is a function of angular displacement.
For a localiser full scale deflection = 2.5 degrees
For a glideslope full scale deflection = 0.7 degrees
For any given angular displacement e.g half-scale on localiser (1.25 degrees) this will represent less and less distance from the centre line (or zero deflection on the loc) the closer to the transmitter that you get.
The the ILS is an incredibly sensitive system. There is a statistic for the size of the box you are trying fly the aircraft through to maintain half scale deflection (for both loc and gs) at a certain distance; but it escapes me now.
On a instrument with five dots full scale (typically in light aircraft) flying just one degree of a radial when tracking a VOR would give half a dot deflection whilst if you were flying an ILS the same deviation would give nearly half scale deflection! The legal limit for continuing the approach.
RBG.