The reasoning as stated was “Transactions which are originated by external party”. Banks are not a third party, they are intermediaries, unless it their own fees / charges.
A Customer sends you a cheque, the reference “cheque number” belongs to the Customer (the third party) not the bank (the intermediary).
A Donation is received in the Bank Account with a Statement reference “A Smith”, firstly this is not a number and secondly if the Bank had assigned 47823876 then that means diddly to either A Smith or the Receiver.
While auto numbers may work with “sales quotes, sales invoices, credit notes, purchase orders, payslips etc” which are internally generated - Cash Transaction like Bank Transaction always relate to a third party so there is an inconsistency in auto numbers one but not the other.
The point is that Manger’s auto numbering should have been implemented to all transaction types as an “audit number” leaving the current Reference field free for ad hoc entry as required by the User’s circumstances. This hybrid cross breeding - some in some out - creates confusion.
A Smith donates cash and it is deposited to a Cash Account and it gets a Manager auto reference
A Smith donates cash and it is deposited to a Bank Account and it doesn’t get a Manager auto reference
Why should the cash in the tin be treated any different to the cash in the teller draw - both are countable transactions.