feat(ins): add remark for ipv6

pages/instances/reference-content/understanding-instance-pricing.mdx

@@ -59,7 +59,7 @@ For more details, visit the [complete Savings Plan documentation](/billing/addit
 ## Instance billing
 
 - Hourly billing starts when you [create the Instance](/instances/how-to/create-an-instance/).
-- Billing pauses if you [power off](/instances/how-to/power-off-instance/) the Instance and resumes when you power it back on. However, **any attached storage or flexible IPs continue to be billed** even when powered off.
+- Billing pauses if you [power off](/instances/how-to/power-off-instance/) the Instance and resumes when you power it back on. However, **any attached storage or flexible IPv4s continue to be billed** even when powered off.
 - Billing ends when you [delete the Instance](/instances/how-to/create-an-instance/).
 
 You can power off or delete your Instance at any time—no minimum commitment or notice period is required.
@@ -70,14 +70,15 @@ At the end of each calendar month, you will be invoiced for your hourly usage th
 
 ### Flexible IP address billing
 
-By default, when you create an Instance, a [flexible IP](/instances/concepts/#flexible-ip) is also created. This public IP address is billed separately at an hourly rate. Check its cost on the [Instance creation page](https://console.scaleway.com/instance/servers/create) or our [pricing page](https://www.scaleway.com/en/pricing/?tags=available).
+By default, when you create an Instance, a [flexible IPv4](/instances/concepts/#flexible-ip) is also created. This public IPv4 address is billed separately at an hourly rate. Check its cost on the [Instance creation page](https://console.scaleway.com/instance/servers/create) or our [pricing page](https://www.scaleway.com/en/pricing/?tags=available).
 
-Hourly billing for a flexible IP begins when you reserve it and ends when you [delete it](/instances/how-to/use-flexips/#how-to-delete-a-flexible-ip-address) from your account.
+Hourly billing for a flexible IPv4 begins when you reserve it and ends when you [delete it](/instances/how-to/use-flexips/#how-to-delete-a-flexible-ip-address) from your account.
 
 <Message type="note">
-  - You can create an Instance without a flexible IP via **Advanced settings**.
-  - Billing for an Instance stops when it is powered off, but its flexible IP remains reserved and continues to be billed unless deleted.
-  - Deleting an Instance via the console prompts you to delete its flexible IP. If kept, billing continues.
+  - You can create an Instance without a flexible IPv4 by unticking the corresponding checkbox.
+  - You can request a flexible IPv6 for any Instance free of charge.
+  - Billing for an Instance stops when it is powered off, but its flexible IPv4 remains reserved and continues to be billed unless deleted.
+  - Deleting an Instance via the console prompts you to delete its flexible IPv4. If kept, billing continues.
   - See the [Billing FAQ](/faq/billing/) for more details on [dynamic IP addresses](/instances/concepts/#dynamic-ip).
 </Message>
 
@@ -95,7 +96,7 @@ Hourly billing for a storage volume begins when you create it and ends when you
 
 ### Estimated cost calculator
 
-When you [create an Instance](https://console.scaleway.com/instance/servers/create/), the estimated cost calculator helps visualize potential charges, including storage and flexible IPs.
+When you [create an Instance](https://console.scaleway.com/instance/servers/create/), the estimated cost calculator helps visualize potential charges, including storage and flexible IPv4s.
 
 <Message type="note">
   The estimated cost calculator provides an approximate sum and does not represent a commitment to spend that amount.