C
Welcome to the forum, you might want to have a look at the following FAQ which explains where everything is
Welcome to Benefits and Work In case you are not aware, your real name appears to be showing in the forum, if you want to change this then follow the instructions in the following FAQ
My full name is showing, how can I stop it?
Benefit Decisions apply from the date that they are made unless there is a good reason for another date to be used, they supersede (replace) any previous Decision, so the scenario in your post is I'm afraid correct.
Have you requested a Mandatory Reconsideration of the Decision?
Gordon