The ‘shared reference’ only comes into play when you select the “split transaction” button (available for Power User accounts).
If you split the transaction between 2 nominals for example, with ‘Shared Reference’ ticked, the reference will be the same for both nominal entries. If ‘Shared Reference’ is unticked, then you can enter individual descriptions for each nominal.
For example, if I had £50 I wanted to split between two nominals, I could do this:
You can see, with ‘Shared Reference’ on, the same reference is used for both entries. If I untick the shared reference box however, I am free to amend each row individually:
However, I appreciate this isn’t clear and will see if we can add this in somewhere.