But that would only work if you can arrange to have the more likely to fail stages earlier in the process. If the last of ten steps fails 5% of the way through,

But that would only work if you can arrange to have the more likely to fail stages earlier in the process. If the last of ten steps fails 5% of the way through, you have wasted 95% of the approval cost. If all the steps are done at the same time and one of the steps fails 5% of the way through you have only wasted 5%.