According to Ted Orland’s poster Photographic Truths: “No two light meters agree.” Sadly, that does seem to be pretty much the truth – unless you do something about it.
For years I had a pair of supposedly “matched” Pentax digital spot meters that were never closer than 1/3 of a stop from each other – so I had to remember which meter I used for film tests and which one I had in the field. One of these meters had an accident and got sent off to its maker for a rebuild – and came back 2/3 of a stop away from where it had been, now 1/3 higher than the meter it had been lower than! So I sent the other meter off to its maker and after two months got it back about the same as when I had sent it. Which meter was right?