Your message prompted me to look up our data. Only have results on 14 2011 born heifers. Our 2010 BIXS data was pretty much of a mess. But I am pretty happy with our 2011 heifer data.
Basically if the cattle sell on a grid AAA is worth a premium and single A a steep discount. AAA = USDA Choice, AA = select and A = standard.
Carcass weight discounts generally start around 950 but can vary depending on orders and supply. 1/2" of backfat is desirable as are USDA YG 1 and 2. 3 is OK, 4 and 5 are usually a discount. If the REA is 14+ the usual reason for 4s and 5s is a long feeding period (beyond optimal). This can be (usually is) related to market conditions, rather than feeding to optimum. I still don't understand it, but when fats go down, most guys feed them longer.
Based on the ages it looks like the cattle were backgrounded, maybe grassed and then finished out. Grades are pretty decent with one or two outliers.