And the variance in effort due to lack of standardization, technical intricacy and hidden complexity is orders of magnitude greater than plumbing so our initial estimates always suck. Most competent proffessional in this insdustry know that nobody knows how to do accurate time estimates on delivering complex software projects, so why don't you know this and why do you want me to lie to you about the crudeness of my estimates?
Frankly, I've worked with hundreds of managers too and you sound difficult to work with. You seem to have unreasonable expectations that are impossible to manage with facts.