Margin negotiation- shall we elaborate the value (money) is going to generate by the other party end of the year? is it a good practice?

Good Question.

Not a bad option either.

You could mention how much margin you could make, excluding costs or Net Profit by explaining a set Target & how much units they need to sell in order to attain a set value. Thus, you are helping them understand the value cycle & it's optimization.

But it would also be very tricky based on the country, type of organization & costings .

Thus, only if you know the territory they operate, the costs they can have, average quantities that could be sold, their target market  & importantly how much of "Profit" they can make out of it.

It may also act as a long term relationship enhancer.

Depends on how well you are able to connect the costings & able to arrive at realistic numbers.

:-)

what if the number is not realistic in terms of value?