What is the allowable deviation in the bay size of a house building?

In residential design, the bay of a residence refers to the distance between two adjacent horizontally positioned walls. Because it is the width of a natural room, it is also called a bay. There are strict regulations in residential design regarding the bays of a residence. According to the "Residential Building Module Coordination Standard" (GBJ100-87), the following parameters are often used for the bays of residential buildings: 2.1 meters, 2.4 meters, 2.7 meters, 3.0 meters, 3.3 meters, 3.6 meters, 3.9 meters, 4.2 meters, etc. Specifying a smaller bay size can shorten the spatial span of the floor slab and enhance the integrity, stability and earthquake resistance of the residential structure. The allowable deviation value of the bay is ±15mm, and the allowable range value is 20mm.