SPD latencies are the timings that is programmed into the SPD chip. The test latencies are the timings that the stick has been tested at. The SPD settings are 'safe latencies' for the stick. It means the stick can run at the defined SPD latency.
But the catch is, most Intel and AMD CPUs don't support speed greater than 1600Mhz and Voltage >1.5V and so sticks are downclocked automatically in order to support the recommended config. The user needs to enable XMP to get the speed, and this config is called 'tested' config.
I was unable to find the SPD latencies of the Trident X ones, so we should compare them with the tested latencies, and they'd be running at tested latencies and not SPD anyways.
For 1600MHz with 1.5V or lower, the SPD latencies hold true, but anything above that, and we'll have to enable XMP, in order to get the 'marketted' speed, and would thus end up having the Tested latency.