accruals

I know that you should take the most recent bill or the bill from last year around the same time when it comes to accruals. But what if ur financials are on lets say December 20×2 (unfinished)the bill before December was October 20×2. I would accrue based on the October bill if i did not have any bill for December. Why edx tell me i should use the bill from Feb.20×3, after december 20×2? Is it because it says unfinished financial statements for December 20×2