Quoted from the article: "The smaller cattle averaged 38 to 40 inches (frame score 2.6) at the hip at fall weaning, and the larger cattle averaged 43 to 44 inches (frame score 4.9). The smaller-framed cows were designated as "range" and the moderately framed cows were designated as "beef." Interestingly, the average mature (6 to 8 years of age) weight was 1,295 pounds for the "range" cows and 1,522 pounds for the "beef" cows."
I would consider the "beef" cows in this study to be moderate also. I would have been more interested in a study with the "beef" herd being frame score 6 1800 lb cows.