The Fixed-Point Tool collects ranges and proposes data types by data type groups rather than individual blocks.
A Data type group is a collection of block paths that need to have the same data type. If they don’t, Simulink will throw a data type mismatch error.
For instance, the output of the gain and the input to the subsystem need to have the same data type (they belong to the same data type group). Otherwise Simulink will throw a data type mismatch error. You can try this by changing the data type of the gain in the attached model to single.
For more details on the data type group, please refer to the documentation link below:
All the shared ranges are an aggregation of the data type group ranges. In this case, shared simulation range is the aggregate of the simulation ranges of the data type group and similarly the shared design range is an aggregate of the design ranges of the group.
Fixed Point Tool proposes a data type that can accommodate all these shared ranges for the group.You can infact click the link at the bottom of the Result Details pane to highlight all the members of the data type group as shown below: