Because the quoted price is not written anywhere the invoice can read. Six weeks later the catalogue has moved, the invoice uses today's rate, and the customer is holding a PDF that says otherwise.
A quotation is a firm, dated offer: fixed lines, fixed prices, an expiry date, and terms taken from the contract rather than a default.
The quotation stamps its rates at issue. Accepted before expiry, the sales order and the invoice inherit those stamped rates, whatever the catalogue has done in the meantime.
A customer on a negotiated rate card asks for a quote. Lines price from their card rather than list, and margin against standard cost is visible while you are still deciding whether to send it.
It will not renegotiate itself. An expired quotation has to be reissued deliberately, so nobody honours a price from last year by accident.
Flow holds the opportunity and the rate card, and acceptance moves the stage. The order, the challan and the invoice all descend from this document.
Yes, on the date you set. It stays visible and can be reissued, but it cannot be converted once expired.
Yes, with the rate stamped at issue so acceptance does not move the price.
They can, from the link. Acceptance is recorded against the document with a timestamp.
Fourteen days, every module, no card. Or half an hour with someone who will run it on your own records and tell you where it does not help.