4 reds on PAPI - NPA in V/S
During a non-precision approach in vertical speed mode, we have a call "500 Continue/Go-around" which in the SOP manual is defined as G/S +/- 1 dot or on PAPI 3 reds or 3 whites. While still in clouds it's pretty hard to tell, but I was noticing we were drifting slightly low on profile. As we get runway in sight I notice 4 reds on PAPI… and just to be sure call "Go-around". This is my first T/R course, so I am not very familiar with airline ops and heavy machinery just yet. TRE in the back asks why, runway is in sight! Me: "Yes..but, oh well… continue then".
So my question is, what is the general idea among line crew if they find themselves low (4 reds) on a NPA when visual? Go-around or just ease off on the descent rate until intercepting normal profile? What is the recommendation for a LST? At first thought, the answer seemed obvious to me "if in the doubt, go-around" and by the textbook I am outside of the parameters for the "500 continue" call. But when a TRE tells you differently it leaves me somewhat confused. I am not completely new to aviation, have about 2000 hrs of instructing so I know it's not an exact science, there are many opinions out there… so more looking for "general (maybe average?) opinion" and, as I said, what do to to satisfy the TRE on a skill test?
Thanks in advance for your help
PS. Just to add, "500 continue" is on top of the regular landing gate at 1000 ft IMC, which is less specific in vertical deviation from profile. Just says "should be on vertical profile".