Why /v2/sizes doesn't returns all available sizes?

Hi, A GET request to “https://api.digitalocean.com/v2/sizes” should return a list of the available sizes. But when i try with

curl -X GET -H "Content-Type: application/json" -H "Authorization: Bearer ****" "https://api.digitalocean.com/v2/sizes" | jq ".sizes[] | .slug"

I get

• “512mb”
• “s-1vcpu-1gb”
• “1gb”
• “s-1vcpu-2gb”
• “s-1vcpu-3gb”
• “s-2vcpu-2gb”
• “s-3vcpu-1gb”
• “2gb”
• “s-2vcpu-4gb”
• “4gb”
• “c-2”
• “s-4vcpu-8gb”
• “8gb”
• “c-4”
• “s-6vcpu-16gb”
• “16gb”
• “c-8”
• “s-8vcpu-32gb”
• “s-12vcpu-48gb”
• “32gb”

I have tried to resize a machine to a not-listed-above “c-16” size and its works! So my question is, why it is missing from the list returned by “/v2/sizes” ?