Just another thought... I did a similar exercise a couple of months ago. You can print a summary AP open payables report at the end of each period and compare the balance with the GL, figure out in which period the balance went out and then take it from there. My approach was to check the balance at each year end to establish in which year it went out, then I took a stab at mid year to see if it was in the first half or second half of the year and narrowed it down from there.