Our nation's laws (state and federal) are premised on transparent, readily available precedent. We have so many rules, statutes, and regulations that the people interpreting these look to how other arbiters decided similar fact situations. Of course, similar does not mean duplicate, so rules of thumb are needed (called the General Rules of Interpretation in tariff classification parlance), as is the logic that was previously employed. It is decision-making by analogy. Previous rulings or opinions are consulted not just because they are helpful, but because earlier precedent must be followed to the extent it is applicable. A precedent is given greater influence if a superior authority within the same chain of command hands it down. It is a Byzantine construct that even lawyers and judges can find dizzying, but its organic, malleable nature allows for limited self-correcting to take place. This is where it pays to use a lawyer. Lawyers, if they are worthy of their licenses, appreciate that there are few absolutes, few areas where the law is permanently, indelibly carved in marble.
A competent legal advocate comes in handy when importers request CBP rulings, sometimes even overturning what appeared to be iron-clad precedent. CBP concedes that it makes mistakes by periodically issuing Revocations Letters published in the Customs Bulletin and on CROSS. CBP appreciates that its own rulings shouldn't even be followed. This is not surprising. CBP officials who issue rulings rarely undergo legal training. They may unthinkingly follow shoddy rulings issued by CBP and ignore court cases that go the other way.
The point is don't automatically give up even in the face of CBP rulings that seem to go against your interests. It's possible that CBP's rulings that bar your way are wrong and are mere eggshells awaiting to be pulverized at the feet of your irresistible logic. View all your submissions, not just ruling requests, to the government as opportunities to advocate. You should not expect great results if you are submitting bare bones, cookie cutter requests for binding rulings. Make your arguments compelling from the get-go. Invoke overwhelming legal precedent to support your stance. There is much at stake. Not only should you be trying to avoid classification penalties (CBP reserves the right to issue these whenever an importer misclassifies imported items even when there is no duty loss), but you also trying to limit any import duties that you have to pay.