Here are measurements from BLF’s well-known color expert “maukka”, who measured the E21A 5000K in a KR4 flashlight, the same model and setup I have. At level 5 out of 7 in his KR4, the DUV measured 0.0004. My measurements of the same output show: [LM3] -0.0045 and [LM4] 0.0003. In this case, LM4 is spot on, while LM3 is off by a large margin.
I’m not claiming that LM4 is accurate; I’m just highlighting how measurements from Opple devices can be off.