They don't sell for the highest possible price, because sales would suffer, they try to sell for the price point that brings them most profit. Adding tariffs will change the point of maximum profit upwards, drastically so for low margin goods.
Companies sell for the highest price they can without losing more sales than it's worth, exactly as you say. I thought it was such common knowledge as not needing to be mentioned.
Adding tariffs means that you might have to lower your profit margins to remain competitive or that you will have to stop exporting to that nation completely, or start manufacturing in that nation. Which is the purpose of tariffs.
