Contract Law Issue

I'm not sure. However, you seem to be referring to contingencies in the contract.

According to William Geldart, Introduction to English Law 146 (D.C.M. Yardley ed., 9th ed. 1984),

"The difference between civil law and criminal law turns on the difference between two different objects which law seeks to pursue - redress or punishment. The object of civil law is the redress of wrongs by compelling compensation or restitution: the wrongdoer is not punished; he only suffers so much harm as is necessary to make good the wrong he has done. The person who has suffered gets a definite benefit from the law, or at least he avoids a loss. On the other hand, in the case of crimes, the main object of the law is to punish the wrongdoer; to give him and others a strong inducement not to commit same or similar crimes, to reform him if possible and perhaps to satisfy the public sense that wrongdoing ought to meet with retribution.”

It is a clause inserted into a contract which allows business or companies to sell goods at different prices. The best example for this could be petrol, as they change their prices everyday.