You did not start age of cow, condition, ect. As a former order buyer , I am sitting there with a order for 25 slaughter cows , it does't matter if a cow comes through with a calf , if she can work in my order , I would buy her and split the calf off resale the calf to lower the cost of the cow. Many many times , I would make a farmer pay more than the pair was worth if he got to bidding against me , I knew more what the cow is worth to me than he would.
I would go call back to the office and find about how the market was working and a just my price up or down the scale as the sale went on. Its a numbers game buy as cheep as u can and sale for as much as u can get. Is it fair yes. One time yrs ago I adjusted the price on my bought cattle 8 times as the market shifted up and down during the sale. I had a order for a load of slaughter cows and the numbers were up on the cows at the yard that day so all the buyers soften the market and bought some cheaper cows for slaughter.