25Live
When looking for location availability in 25Live Event Form, it does not compare the expected headcount of the event to the maximum capacity of each location except as a warning after a location that is too small has been selected, and this warning is not related to layout capacities themselves–only the location's maximum capacity. It's up to the assigning scheduler to know whether a given layout is too small for their event needs.
Schedule25 Optimizer
When the Schedule25 Optimizer (found in X25 Analytics) looks for space availability during a run, it compares the expected headcount of the section to the capacity listed in each location record, unless a default layout has been specified. In that instance, the algorithm looks at the capacity of the default layout.
Best Practice: Make the Maximum capacity of a space the SAME as the capacity of your default layout.
Layout capacities are useful for displaying (in 25Live) the different capacities of each layout in a multipurpose space. However, in order to ensure consistent system-wide functionality in Series25 it is best to follow this practice. It will provide consistent scheduling in the 25Live Event Form, and appropriate Schedule25 placement. If you wish to track something like Fire Code Capacity, this is best kept as a Location Custom Attribute.