Death compensation: refers to the surplus generated when the actual number of deaths is less than the scheduled number of deaths. Expense differential income: the expense differential income generated when the actual expense rate of the company is lower than the expected expense rate. Spread: when the actual investment interest rate of the company is higher than the predetermined interest rate of the policy, the spread will occur. Total difference income: the dividend of capital preservation and dividends comes from all the surplus that may be obtained from the operation of dividend-paying products, that is, "total difference", including "three differences" and other possible surpluses.
Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.