Use a consistent vector indexing method for all blocks.
When possible, use zero-based indexing to improve code efficiency. However, since MATLAB® blocks do not support zero-based indexing, one-based indexing can be used for models containing MATLAB blocks.
Verification and Validation
By Task > Modeling Standards for MAAB > Simulink > Check for indexing in blocks
For check details, see Check for indexing in blocks (Simulink Check).