The unintended effects of project cost accounting on the collection of useful project task time data for future planning purposes

I'm trying to solve, what i believe to be a common problem, where cost accounting policies conflict with individual or team performance management policies / structures.

As an example, I have found some companies to have policies that require employees to record a percentage of their total time toward billable projects (80%). These same companies diss-incentivize their employees for recording more time than was allocated toward a project by reducing bonuses or public embarrassment. The result is that the employees / managers look for ways to make their projects "look good" by falsely recording their project time. They rob Peter to pay Paul by charging more time toward projects with more unused hours and less time on the project that they actually worked on.

The unintended result of all of this is the collection of erroneous task / project time data. The data collected may have been useful in making the project look good but it is no longer useful for future project bidding or scoping purposes.

What i am wondering is if you are familiar with any time accounting processes or incentive plan processes that are designed to alleviate this problem.