公司合約其中一項寫明3. Basic Salary, Commission, 13th Month

之後有一個細看又寫明13th Month: A 13th month based on your basic salary and indexed on individual and company performance. It is discretionary. At the time of payment and in a continuous employment situation, should the service be less than a complete year, the 13th month will be calculated on a pro-rata basis equivalent to the length of your completed months of service at the time of payment. Should you resign prior to the completion of a service year, or not complete the probation on the cut-off date, you are not entitled to any part of this 13th month payment.
Payment will be made provided you are still employed by the company at the time the payment
made. Employees who are dismissed by the company will not be entitled to any 13th

咁即係公司係咪一定要俾雙糧定係可以當花紅甘比？我做左2年幾，因為我理解嘅雙糧嘅英文同埋花紅個英文唔一樣，如果個合約寫左13th month，係咪代表就算佢個合約之後加左呢堆野都可以唔比，然後當花紅甘出？咁就唔叫13th month啦

雙糧：Double pay, 13th-month pay, Year-end bonus
花紅：Bonus, Performance bonus (績效花紅)
酌情性花紅：Discretionary bonus (不保證發放)
按比例花紅：Pro-rata bonus