Any basis used consistently can probably give consistent and comparable results.
However if one uses the definition of Consistency as say, Reliability or uniformity of successive results or events, then you then have to consider reliability and uniformity.
Then in my example the first person scoring 47 in each innings is consistent by definition and the other who scores big occasionally is not.
I do not see you have to score a 50 to be classed as consistent.
By your definition then yes but by the pure definition of consistency then I do not agree.
You have set 50 at the bottom threshold and my question is why?
You might say who monitors 47s and the answer would be, at the moment, practically no one.
However whatever basis of measure that is universally agreed would be the measure.
This measure of consistency is your measure and forms a nice platform for discussion.