We can work with you and add any necessary code to do that kind of setup.
Currently, in the e-commerce app you can add items and require a subscription for them, with options to set the duration and pricing for each. So based on what you are saying, I think you want a section for the members to check out their subscription, and what is in it/edit it if they want? Kind of like the subscription models that allow x number of items, and the customer chooses the items?
Please confirm, and then we can confirm the feature add and estimated time it would be ready. There would be no added charge for the new feature; it would be added as a new feature to UltimateWB Full, so upgrades would be easy for you too - no special requirements!