UKVCAS appointment- priority and super priority

Hi,
I’m going to submit my application for ILR but still don’t understand the difference between priority and super priority service (if any) in terms of the appointment (I understand decision lead time)
In both cases do I have to book an appointment in a UKVCAS centre? In that case both are subject to the same appointment availability and cost? When i read the application, I understand priority service doesn’t need appointment but sending documents only -is this correct? Or are those the same appointment centres and the decision time is the only difference?
Thanks

For Super Priority OR standard service, you have to book an appointment at UKCVAS, regardless of what you are applying for and you have to upload your documents online. Nothing is sent by post. The purpose of the appointment is for biometric enrollment and identity check.

Super Priority costs an extra £800. Note that this is SEPARATE to the appointment cost, which can vary from free to over £100.

There is no 'priority' service for ILR. You only have Super Priority or 8 week standard. The service you choose is only relevant to the processing time.