The phrase "additional concessions" means extra compromises or agreements made in addition to what was previously agreed upon. These concessions are made to accommodate or please someone further. Full definition
What the prospect is hoping that you'll offer additional concessions rather than lose the sale. (inc.com)
Your credit score is used as a component whether or not a bank will choose to approve a loan or may force you to make additional concessions for approval. (valuepenguin.com)
They must now offer additional concessions or face potential fines. (marketingland.com)