This gives me nightmares

The Pioneer Valley Regional School district just discovered that they have nearly a half a million dollar budget gap:

Pioneer Superintendent Ruth Miller, entering her first school year in the job, discovered the budget deficit after she was hired earlier this year.

The gap comes in large part from state aid, school choice and debt service projections that were off.

But Miller hopes she can close the gap through some new “efficiencies” in operations and from grants she expects to get this year but that aren’t figured into the budget.

The district has to pay $477,487 more than it anticipated because revenue is now calculated at $15,064,581, while expenses total $15,542,068.

Here's what I don't get: state aid is a straightforward calculation. Unless, as was suggested to me yesterday, you were counting on the Legislature to pass a larger minimum per pupil amount, it's hard to see how that one could go wrong. School choice, certainly, can shift, but by half a million? There's some unanswered questions about process here.