Dream Land, the accuracy of the ILS is not dictated by DH. The system installation requirements will require some margin of accuracy below any operational use height.
Ref landing dist / PAPI; refer to the
airport chart. The ILS threshold is displaced; this gives a LDA of 2610 m vs the runway length of 3120m. If an operator is authorised for IFR operations into Quito then the landing performance on runway 35 should match this reduced value, enabling a stabilised instrument approach and transition to the same stabilised visual approach path.
The standard requirements (ICAO?) for lighting on an instrument runway is that PAPI matches the ILS GS; if not, this deviation should be identified on the chart. I see no evidence of this. Even if the PAPI and ILS were not aligned, then the landing performance aspects should not require any duck under manoeuvre.
The ILS GS is 3.1 deg, nothing unusual; thus with appropriate performance calculations (noting tailwind) and accurate flying, then landing from a stabilised approach should not present any greater difficulty or risk than in other operations – perhaps excepting the higher grnd speed / reaction time. i.e. the margin for error in airspeed, TCH, touchdown position, spoiler / reverser deployment, is reduced.
Certificated landing performance is normally limited to 8000ft amsl. This can be extended by extrapolation usually with additional margins. Whilst most manufacturers can extrapolate for their aircraft types, the resulting performance might be uneconomic. However, IIRC Airbus conducted actual landing tests at Quito, thus normal certification rules would be expected to apply.