Note that NIC rates update when a stopped instance changes compute offering

- Network Throttling: state that the NIC network rate follows the new
  compute offering when the offering of a stopped instance is changed
- Changing the Service Offering for an Instance: add a note linking to it
- Restore the network-throttling label, now referenced from the
  instances page

Author: sudo87

source/adminguide/service_offerings.rst

@@ -671,6 +671,8 @@ but with some fields pre-filled with the settings of the existing offering.
 You can modify any of the settings as needed before clicking Add to create the new offering.
 
 
+.. _network-throttling:
+
 Network Throttling
 ------------------
 
@@ -738,7 +740,9 @@ Additional networks of a guest instance      Compute Offering
 
 Since 24.0.0, the Compute Offering network rate applies to every network of
 an instance, not only the default network. If the Compute Offering has no
-network rate, vm.network.throttling.rate is used.
+network rate, vm.network.throttling.rate is used. When you change the
+compute offering of a stopped instance, the network rate of its NICs is
+updated to the rate of the new offering.
 
 A guest instance must have a default network, and can also have many
 additional networks. The compute offering network rate applies to all of

source/adminguide/virtual_machines.rst

@@ -508,6 +508,11 @@ Instance, you can change the Instance's compute offering.
 
    For more information on how to prevent this, see :ref:`strict-host-tags`.
 
+.. note::
+   Since 24.0.0, when you change the compute offering of a stopped Instance,
+   the network rate of its NICs is updated to the network rate of the new
+   compute offering. See :ref:`network-throttling`.
+
 .. _cpu-and-memory-scaling:
 
 CPU and Memory Scaling for Running Instances