Distributive approach to negotiation used when the interested parties are attempting to divide something up or distribute something of value, also known as zero-sum approach or win-lose. Commercial situations often demand a distributive bargaining approach, if the 'pie' is inherently of a fixed size. In this case, any conflicts must be resolved by sharing it.
In win-lose approach, a negotiator wants to maximise the value obtained in a single deal, the relationship with the other party is not important. Therefore, a strong party may win more than 50% of the metaphorical 'pie'.
It should not be assumed that win-win can be applied to all commercial negotiations, or that win-lose approaches are inherently inferior.

Giving positive group and individual feedback is easy, as is self-congratulation and, in many cases, it is hoped, this will be an accurate reflection on actual performance. When it comes to developmental or difficult feedback, it is only natural to want to move on and not reflect on the negative or developmental points, or why a negotiation did not achieve its objectives. But this is a mistake. The best learning opportunities come from reflection on what could be done better, and this can be achieved without blame, threat or condemnation.
Everyone and every team will make mistakes and/or have areas where they could have improved. Clearly, if every reflection session concludes that an individual or team keeps making the same mistake, then there is a case to change roles or consider alternative approaches.
About Dos and Don'ts of reflection, you can refer here: https://offices.depaul.edu/human-resources/employee- relations/Documents/Self%20Assesement.pdf

Reference: CIPS L4M5 Study Guide, Section 1.2 - Approaches to Negotiation

The agency (buyer) has made a concession about the price. Possibly the supplier will request another concession (the salami tactics). To avoid this to be happened, the agency should only allow a concession as an exception, make sure that the concession is documented and only permitted against some exceptional circumstances, and seek agreement to this from the supplier.
LO 3, AC 3.2

This is a closed question because it requires a definite, factual response such as "yes" or "no". Closed questions are particularly useful in negotiations for confirming specific commitments, including delivery dates, prices, quantities, or contractual terms. They reduce ambiguity and are commonly used during the later stages of negotiation to confirm agreement and progress toward closure. Probing questions seek deeper explanation, leading questions influence the answer, and multiple questions combine several issues at once.
CIPS highlights the importance of choosing question styles appropriately depending on the negotiation objective and stage.
Reference: CIPS L4M5 Commercial Negotiation (CORE), 2nd edition - LO 3.2: Questioning techniques and effective communication.