Welcome to the Community Forum for PP members.
If you want to increase your DD payment then you need to do this via your App. Go to Help and open Ask WattBot
Then type "Message the team" and send, and then request an increase to your DD.
Please note that by changing your "warmer months" DD this will automatically increase your "cooler months" DD.
You have not indicated why you think you need to increase your DD payment, so it's not easy for anyone to give you a better idea of what you are best to do.
If you post more information then a better solution may be possible to advise on.