Promoting 'small portions' and 'half portions' may indeed add a certain amount of time and cost in terms of manpower and material resources to the catering industry. Specifically, this can be illustrated in the following aspects:

1. 'Small portions' and 'half portions' require additional preparation and processing. Restaurants need to increase the types and sizes of dishes, and need to cut and process ingredients in different proportions. This will increase the labor cost and the cost of purchasing ingredients for the restaurant.

2. 'Small portions' and 'half portions' require additional service and management. Restaurants need to increase the identification and service of different sizes of dishes, and need to train servers and food servers, increasing the cost of management and distribution in the back office.

3. Promoting 'small portion' and 'half portion' will also increase the publicity and promotion cost of the restaurant. Restaurants need to publicize and promote new dishes to attract more customers to try them.

4. Although the promotion of 'small portion' and 'half portion' may increase the cost, it also has some benefits. Firstly, it can meet the needs of different customers and increase the competitiveness of the restaurant. Secondly, it reduces the wastage of ingredients, which can reduce the cost of the restaurant. Finally, offering 'small portions' and 'half portions' can also provide customers with healthier eating choices.

Overall, the promotion of 'small portions' and 'half portions' may increase costs, but it can also bring benefits to the restaurant, especially in terms of meeting customer demand and reducing food waste. Therefore, restaurants can make decisions and implement them according to their own situation and market demand.