This seems to be the confusion. When BRS tested it was ULR Phosphorus vs LR Phosphate.I don’t believe the new model was out when that video comparison was made.
ULR Phosphate should be the same test as ULR Phosphorous without conversion and better timer. Not 100% but in the past Hanna always updated models this way. (Alk in ppm vs dKH, etc).
With that said ULR Phosphate states 0.02ppm phosphare accuracy vs ULR Phosphorous's approximately 0.015ppm accuracy (5ppb phosphorous * 3.144). But I think this has to do with rounding since ULR phosphate can only view to 0.01.