To keep things easy, the costs of all your channel packages are combined and billed together.
Your first bill after you upgrade with add-ons includes the following:
The next month’s cost of your Philo channel package.
The next month’s cost of your add-on channel package(s).
The previous month’s pro-rated cost of your add-on channel package(s). In other words, the back-billed, partial cost that is proportional to the time period between the trial end date and the billing date.
After this initial “balloon” payment, all the following bills are just the next month’s costs of your Philo and add-on channel packages.