You are entitled to appeal and/or request an internal review of any decision made by a SW Deciding Officer. You are required to state the grounds for your appeal and provide any new facts or further evidence in support of the appeal that you may have.
However, in order to win an appeal, you'd normally have to satisfy the Appeals Commissioner that the original decision made was incorrect.
In your case, as your appeal seems to based only on the definition of the Governing Contribution Year* in the JBSE scheme, it's hard to see how it could succeed, given that the decision appears to be in compliance with the terms of the scheme.
* Definition of Governing Contribution Year
The Governing Contribution Year (GCY) is the last complete contribution year before the benefit year in which the claim was made. A benefit year begins on the first Monday in January in any calendar year and ends with the Sunday immediately before the first Monday in the next calendar year, e.g. for claims made in 2021 the GCY is 2019.