Dynamic function cannot access needservice need types

[jumbo172]

I have a custom needservice that mines JIRA tickets and writes data to each requirement need.
I have a dynamic function that manipulates data of the 'components' option of each requirement need and updates the need 'in place'.
This ensures that the data for needs has been processed inside conf.py and is not reliant on any dynamic functions called from directives inside rst within the document.

The dynamic function is called like this:

needs_global_options = { 
   'components': ('[[convert_jira_components_to_list()]]'),
}

And is registered like this:

def setup(app):
    add_dynamic_function(app, convert_jira_components_to_list)

The issue is that when the dynamic function is called using global options:

needs_global_options = { 
'components': ('[[convert_jira_components_to_list()]]', 'type=="requirement"'),
}

The requirement needs generated by the needservice are unavailable in each need variable. I have other requirements not generated by needservice and these are available in each need variable.

So the workaround is to use the needs variable in the dynamic function. I can then loop over each need of the needs variable.
The problem with this is that the dynamic function is called for every need type in the filter, so it executes multiple times. I have to put in extra code to restrict the function to only execute once.

This works, but it's ugly for 2 reasons. Firsty the execute once restriction, secondly I am using needs_global_options to return values to the 'components' option, but I am not returning anything and updating the need in place.

Is there a reason why needservice needs are not available in each need variable inside dynamic functions, but other needs are?
Is there some way to ensure that a dynamic function gets called just once, not for every need?

Thanks