Protection doesn't have static DR based on rating. It depends on what kind of hit you are taking (which the information in-game states). From my lunchbreak testing, on the first boss in Polaris elite and the addpack before that I came up with these results:
Bear in-mind this isn't hundred percent accurate, but it gives you an idea of what is important here.
The small adds hit me for about 100, while the first boss hit me for around 800 with base physical protection. The second time I did the exact same thing only with around 750 protection. This time the small adds hit be for about 88 (which seems to be in line with what you've posted), but the boss which previously hit me for 800 now hit me for 580 a hit.
It seems to me, the harder the base attack, the more mitigation in percentage you get in return. If that is true, protection is increasinly more valuable against hard hitting bosses, while evade might come out top against a pack of low hitting mobs/bosses.
Here's some random values of what I get hit for today with 612 magical protection + minor ward + debilitate:
DemolishMachine Tyrant NM) Max 9.5k unmitgated |lowest (Stoicism + blocked) 3.5k.
Searing Brand: Max hit (- debilitate) 7.1k | Min hit (Stoicism + blocked) 2k.
Machine Tyrant with 847 physical protection + minor ward + debilitate:
Max hit 2083 (crit) | Min hit 147 (Stoicism, 17 % Ablation, 4 % Salvation, Block, Evade proc (I giggled here)) |Median 1148
Max hit 2070 | Min hit 1088 (Stoicism + blocked, 4 % Salvation) | Median 1513