It will upgrade to the next level automatically and stay at that level until you downgrade. If you no longer require the next level of forms, you can downgrade at the end of the billing cycle for your account back to the free level.
Thanks for the info.
Does this also apply if we switch to “Pro” plan for a couple of months when we expect higher bandwidth usage? Can we downgrade anytime (at the end of the billing cicle) when we don’t need the extra bandwidth?