LMSC I can’t see the raw data, or sampling method details there, not sure why they tested with sucrose as only the dual scale Atago shows Brix v TDS, the other devices do not display Brix.
Looks a bit confused & sloppy to me.
Why 19 samples on the instant?
Why test 5x R2 but only 1 each of the others?
Not trying to convince you, or anyone else of the usefulness of the R2, A bigger study than my test would be better, but this doesn’t look like it.