RE: Sales and Invoicing batches
Cynthia,
Both Sales Order Processing and Invoice Entry pass transactions to Accounts Receivable. Sales Transaction Entry processes Sales Batches and Invoice Entry processes Invoicing Batches. The Sales and Invoicing Batches allow for the storage and handling of transactions entered in their respective modules.
As Frank mentioned the main difference between SOP and Invoice Entry are processing options, support for types of transactions and other enhanced features.
If the client has simple invoicing needs, and straight forward pricing, then Invoicing will typically meet the client's needs.
If the client has complex order to cash processes, complicated pricing requirement or multi-bin inventory needs, then Sales Order Processing with Advanced Invoicing (the modules full name) is the right choice.