Subscription Rate vs Revised Rate 7.9.12

Two questions:
1) What sets the Subscription Rate speed in this context? I noticed in the help manual that the Subscription Rate is 1000ms in the example given, so just wondering why or how mine is set to 250ms. Is it all device driver based?
2) What is the Revised Rate? I am assuming the Scan Class rate.

Note: All 227,000 tags in the project show a Subscription Rate of 250ms but we have about 15 different scan classes… (Using the default RSLogix 21+ driver and Ignition’s OPC-UA)

As you were…