You should use this mode for conditionally creating rule objects according to rules, or where the initialization attribute values are calculated from other rules, or where the rule object is only an interim step in a calculation.
For a very complex calculation, you should expect to have one external rule object holding an attribute for the calculation result, several external rule objects for input data from outside of rules, and possibly a very large number of internal rule objects for the intermediate calculation steps.
If you have rule objects which will always exist and/or require to be accessed by readall expressions, then consider creating external rule objects directly in your code instead.