In principle, the date of signing the transaction, or another date that is sufficient to determine the transaction object and transaction amount shall prevail (whichever is the former).
In principle, the date when the transaction is signed or the date when the transaction partner and transaction amount are fully determined shall prevail (whichever is the former).
In principle, the date of signing the transaction or the date on which the transaction object and the transaction amount are determined (whichever is the former).