Clarify apps / services / instances per tier

Can you clarify the distinction between apps and services and how this relates to instances and pricing tiers? I hit the limit saying ‘max 3 apps’, but apps are not mentioned in your pricing plans and do not seem to be displayed in the dashboard anywhere. My use case is spinning-up a container from a registry for each end user. So for example it is not clear whether ‘100 services’ (shown in your Pro plan) means potentially 100 concurrent containers. Somewhere else in your documentation it also says up to ‘16 services for each app’, which for max three apps is only 48 services.

If each end customer were to be pulling down a unique container to be run just for them, does your Pro tier support 100 concurrent end customers?

Thanks