You are correct. "Cover" is what determines pull back. Although one heat may also be a factor. Cover (for me cover is quality as I prefer my $1.99 per pound buying more meat then bone) is most important. Can be from an unfinished animal, or a poor cutting at the slaughter house. But cover is definately the factor I key on the most for preventing bone creep. AKA pull back.
To many people pay no attention to meat quality and yields. They think $1.99 per pound is good pricing, it may be, but most likely it is not, here is why:
Cover is important cause in the catering world, prie per pound of yield is everything. People don't eat bones (alright most people) so if you are cooking $1.99 per pound ribs with a 40 percent yield (0.40 pound of meat per pound purchased.) You actually have $4.98 per pound yield.
Take a look at John Morrell or IBP ribs at $2.50 per pound ribs but with good cover they produce a 65 percent yield. (0.65 pound of meat per pound purchased) You are now producing $3.85 per pound yield.
While it may not look like the $2.50 per pound is the best deal, knowing yields from different cut shops by watching what happens to the meat you purchase allows a very different calculation. At you own home you would save $3.39 on three pounds of rib meat consumed by knowing what the yields are and selecting the highest yield per pound.
But for me in Catering. If I am feeding of 400 people, I know I need 200 pounds of meat yield. I spec John Morrell or IBP, so I get to order 310 pounds of ribs to get my 200 pound yield.
I have $775.00 tied up in rib costs for the feeding.
A competitor that makes these mistakes either runs out of food (kiss of death in catering) or over orders because they know the low yield but always go for the low price.
The competitor will have $995.00 tied up in the $1.99 per pound type ribs. And it adds up from there... they also have to prep more racks, use more spices, cut more finished ribs.... etc etc.
And that is why I have purchased the equipment of four other food service companies at auction for 10 cents on the dollar. They tried to compete thinking it was about low cost food selling for a higher price than purchased. But it is yield that counts and seperates the winners from the also rans!