The Boeing 767 was established on the ILS glide path to runway 27 in VMC. The crew noted that the visual approach angle appeared shallower than normal for the aircraft configuration and consequently had the crew flown the aircraft in accordance with the ILS indication, the aircraft would have probably landed short of the runway. The crew also noted that the Precision Approach Path Indicator indicated a significant undershoot. Several international crews have reported contradictory indications on the runway 27 ILS glide slope and Precision Approach Path Indicator (PAPI) guidance systems. The crews believe that the Den Pasar runway 27 ILS glide slope and PAPI may be unsafe for use in IMC. Consequently, Bali Air Traffic Services have issued a NOTAM stating that the runway 27 ILS glide path is unreliable and awaiting further testing.