[pxx]

The cardinality of one set is much bigger than the cardinality of the other one. Pantone 871 is mapped to #84754e. If you see #84754e and also get the instruction "use only Pantone colors", it is not ambiguous!

[chrisseaton]

Someone needs a lookup table to map those back - that’s what you’re paying for. They aren’t claiming to ‘own’ the colours.