I agree with Beagle here, the wording of the relevant clause is ambigous and could , I think, be argued pretty well by a clever lawyer.
3.3.2 IMC Rating Holder in Current Practice
3.3.2.1 Pilots with a valid Instrument Meteorological Conditions (IMC) Rating are recommended to add 200 ft to the minimum applicable DH/MDH, but with absolute minima of 500 ft for a precision approach and 600 ft for a non-precision approach.
The way it reads to me is that it recommends that you add 200', this is only a recommendation and therefore you do not have to adhere to it. However the 'but' followed by 'absolute minima' suggests to me that 500'/600' must be adhered to.
Any legal eagles on here can clarify?
the ILS is more sensitive below 500ft and thus requires a bit more ability to fly accurately.
When you are this far down the ILS its that sensitive I doubt you would really notice the difference. If you are current and flying the ILS with small inputs you should be holding the needles without too much variance anyway, if they swinging wildly - suggest you get an instructor.