Yes! We want to make it easy for you.
There are two options:
1) You want to go from Free plan to a paid plan. In that case, the apps that you were tracking during your free plan are preselected, but you have the option to delete them to start afresh when upgrading;
2) You want to upgrade from one plan to the next. Then, all your apps are automatically transferred to your new plan, and you can continue adding apps within the limit of your chosen plan.
You don't need to manually add your previous unlocked apps, they are automatically added to your new plan.