Well you hadn't really explained that at all - I re-read the thread, and there is little to no explanation.
The normal approach here would be to store the "Potential order" or "quote" lines with a flag or unfilled out field to indicate that it hadn't been confirmed. The calculations can be part of the form.
If the client proceeds you simply update the potential order by updating a ConfirmedDate or similar per order line. No need to do any more or less. You have a record of what you quoted and the quantities, and it's a simple matter to move it forwards to an actual order.
If this isn't what you need it to do please describe the whole process so we can make sensible suggestions.