The numbers you come up with might not be an end in themselves, and maybe Japanese do take it to an extreme, but there is value in trying to quantify the uncertain (e.g. forced estimation, consideration of alternatives, benchmarking).
Example: From a discussion of Japanese management practices by a former executive level employee of several Japanese companies.
Source: Rehfeld, J.E. (1990). What working for a Japanese company taught me. Harvard Business Review, Vol. 68, No. 6, pp. 167-76.