I found this blog post at Pro Publica to parallel concerns about using the same acreage reporting process for both FSA and crop insurance. The logic is the same: Social Security Administration has a process for determining whether someone is disabled; Education has a provision to forgive student loans for those who are disabled; why not piggy back the student loan forgiveness on the SSA process? Sounds good, but as usual there are good bureaucratic reasons not to, at least according to Education.
I suspect the reality might be that Congress, the public, and the bureaucrats all are envisioning an over-simplified perfect world. If someone looked at the situation worrying about margins of error and marginal returns on investments, the end result might well have been different. But that's not how we usually look at things, much to the dismay of economists.