Fraser' do you really take this as an class-reference mark?
I just did a quick test on my room wall with my cheapo PIR-thermometer (which has ε 0.95 hardcoded). It measured 27°C.
-an el cheapo PIR thermometer with hardcoded 0.95 ε
Don't get me wrong I adore el'cheapo PIR thermometers, got a bunch of them myself and some of them cost sub 10bucks delivered and use them for all sorts of stuff, not least in the kitchen, but they are all over the place inaccuracy, would be a shame to set a single el cheapo as a reference-class and set the world in motion with returns to seller etc. if you haven't concluded there in fact are a problem,.
Anyway, the measurement I have made with Compact pro often tend to be 3 to 5 degrees lower, if I am at some distance and above 60degree, up close like +/-1 a meter, its usually a degree or two off.
But that seems to be the norm with many mobile thermal-attachments, as mentioned the highly praised and superb Thermp App TH and a 2000 USD device was massive -14% (43*) off at 50 degree in MJlortons video and that was around a meter in distance.. it did afterwards perform way better readinga higher in degree like 120 and 200degree... if you seek accuracy, and something there is reliable all over the spectre and at numerous distances' then it's likely not the mobile versions there are the obvious choice.