For me this seems like the most obvious thing the billing system is missing.
Not every company bills all customers on the same date, and in Australia it is standard practice to bill from the service activation date.
As far as I can tell so far in Splynx the billing start date needs to be set. I realise it might be possible to do this with the API but that is another problem to which I currently have.
Surely it would be very simple to implement an option in the billing defaults and customer billing page that instead of selecting billing start date as a number you could select "start billing from account creation date" or "Start billing from service active date"
This would really help me if this was implemented.