Life insurance recommendations are calculated to provide the survivor with the per-adult equivalent living standard compared to the household discretionary spending with both adults alive. The default economy of scale is 1.6. That is, two can live as cheaply as 1.6. Where a household discretionary spending is 100,000 the per-adult equivalent that needs to be insured for the survivor is 62,500. 

When a special expense is created, it moves available spending out of discretionary over to fixed expenses. One can see this in the Spending Overview where the expense appears in the Other column among fixed expenses. Say this was a $30,000 expense. In a survivor report, this full $30,000 needs to be funded by the survivor. It's not subject to the factor of 1.6 economy of scale. If the $30K was for a car, the car still costs $30K with or without two adults. 

This points to the problem of trying to put household expenses like "groceries" in Special Expenses. In such a case, the survivor doesn't need $30,000 to fund the grocery cost with one mouth to feed instead of two. The survivor is one, not two, and the cost needs to be scaled back by the factor of 1.6.  Otherwise, on a per-person basis which is the basis of life insurance, the grocery bill just went way up! And, consequently, life insurance may go up to fund this extra expense. 

This is where Contingency Planning comes in. You could enter this annual grocery expense as a Special Expense, but a contingency should be added so that in the event of one death or another, the new cost of the groceries becomes 18,750 which, per the household economy of scale, is what it takes to buy equivalent groceries for one instead of two persons. 

See also: 

How to Adjust or Disable Life Insurance

How do contingency settings affect my plan?

Special Expenses and Receipts