Final answer:
When requested, extra or light toppings are adjusted by a percentage of the original amount, typically around 10%, although this can vary by establishment or customer preference.
Step-by-step explanation:
Generally, if there is a request for extra or light toppings, the amount to add or reduce is typically a certain percentage of the original amount. For instance, an establishment may choose to add or reduce toppings by 10% if requested. This means that if a recipe calls for 1 cup of marinara sauce and a customer requests a light serving, only 0.9 cups of sauce would be included, which is a 10% reduction from the original amount. Conversely, if an extra amount is requested, 1 cup would increase by 10% to 1.1 cups. This percentage is not a fixed rule and can vary depending on the establishment's policy or the customer's preference. Therefore, it is important to clarify the specifics with the customer or follow the provided guidelines of a recipe or establishment.