fix(nats): correct pricing

Author: RoRoJ

pages/nats/concepts.mdx

@@ -21,6 +21,14 @@ Credentials give services and platforms access to Scaleway NATS, enabling them t
 
 A message broker is a piece of software that allows applications, systems and services to communicate with each other and send/receive data. It facilitates the exchange of information by receiving messages from a producer, and transmitting them to a consumer. Scaleway NATS is a message broker tool based on the NATS messaging system.
 
+## Message volume
+
+Message volume is one of the factors affecting the billing of Scaleway NATS. Message volume is calculated as the number of messages sent to/received by NATS, multiplied by the message size. Or, the sum of the size of all messages passing through NATS.
+
+## Message persistence
+
+Message persistence is one of the factors affecting the billing of Scaleway NATS. Message persistence is calculated as the total amount stored in NATS, multiplied by the duration it is stored for.
+
 ## Messaging and Queuing
 
 Previously, Scaleway Messaging and Queuing was a single product that grouped together three different messaging protocols. It has now been split into three distinct products: [NATS](#scaleway-nats), [Queues](/queues/), and [Topics and Events](/topics-and-events/).
@@ -59,12 +67,4 @@ Check our our [NATS quickstart](/nats/quickstart/) to get started with Scaleway
 
 NATS includes the JetStream feature, an add-on to its pub/sub model which implements message streams with persistent messaging capabilities. Distinct from traditional message brokers where messages are deleted once received/consumed, streams retain records ("persistence") of their events. A streaming broker is therefore often likened to a distributed append-only logs file, where every new message is added at the end of the persistent log. Consumers can be thought of as “cursors” in the stream, consuming the stream’s messages according to their filters. 
 
-With NATS, you would typically implement a queue as a stream with a single consumer to read from.
-
-## Stream volume
-
-Stream volume is one of the factors affecting the billing of Scaleway NATS. Stream volume is calculated as the number of messages in a stream, multiplied by the message size. Or, the sum of the size of all messages in a stream.
-
-## Stream persistence
-
-Stream persistence is one of the factors affecting the billing of Scaleway NATS. Stream persistence is calculated as the total amount stored in a stream, multiplied by the duration it is stored for.
+With NATS, you would typically implement a queue as a stream with a single consumer to read from.

pages/nats/faq.mdx

@@ -26,6 +26,6 @@ The **N**eural **A**utonomic **T**ransport **S**ystem, or [NATS](https://nats.io
 
 ## How is Scaleway NATS billed?
 
-Billing is based on [stream volume](/nats/concepts/#stream-volume) (the total sum of each message's size going through the stream) and [stream persistence](/nats/concepts/#stream-persistence) (the total amount of data stored * duration).
+Billing is based on [message volume](/nats/concepts/#message-volume) (the total sum of each message's size going through NATS) and [message persistence](/nats/concepts/#message-persistence) (the total amount of data stored * duration).
 
 For full pricing details, see our [dedicated pricing page](https://www.scaleway.com/en/pricing/).