GD, you are asking the wrong question.

It doesn't matter two hoots which meter gives the correct indication. Almost
certainly neither of them do. And if by some remote chance their indications
were identical they would be no more likely to be correct.

But your transmitter will feel far safer, much happier and comfortable, if
its own internal meter, provided by the manufacturer, is used for tuning-up
purposes.

The purpose of the meter is NOT to measure SWR on a transmission line which
doesn't exist, but to indicate whether or not the transmitter is loaded with
its correct value of resistance.

( The best way of checking a so-called SWR meter is to locate it as near as
possible to the transmitter and replace the feedline+antenna with a 50-ohm
resistor.)
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Reg, G4FGQ