Checkbook reconcilliation or accounting problem

What’s the right way to account for the following situation in reconciling a checkbook?

By my records I have debits to Amazon.com on three different days for three different amounts.

By their records there are seven different debits on five different days for seven different amounts.

There are no instances of an amount on my list matching an amount on their list.

I tried hunting around the hard way for instances of two of their amounts totaling the same as one of my amounts, but did not find any. Then I started hunting for instances of three of their amounts totaling the same as one of mine, but this got so hard to keep track of that I gave up after a little while. I also tried a running subtotal for my list and their list, both on the basis of transaction date, but didn’t get any subtotal for mine matching any subtotal for theirs. In previous months, these strategies have allowed me to match everything up, but this time it’s too messy.

I might try writing a computer program that identifies subgroupings in each list that have the same totals. But I assume other people don’t do it that way.

So, what is the proper thing to do?

BTW I wound up creating a new transaction for my records, for the total amount in their list, and marked it as cleared, and marked all their transactions as cleared on my paper statement. This makes the statement look balanced. Then I created a new transaction for the $15.58 difference between our lists, so that if my records were correct and there is still a little charge floating out there, it will match when it does clear. But this is giving me the same headache I used to get when my accounts were a big mess and I never knew what I was doing, all those decades ago. It’s maddening because until this morning I had nearly 20 years of computerized bank records that always added up correctly.

Don’t know about the accounting side of the issue, but trying to find a subset of numbers that adds to a given total is called the Subset Sum Problem and is NP-Complete. (I.e., it’s apparently as hard as you think it is.)

I’m an amazon.com junkie and one thing that you can do is delay the recording of your debits on your side until after the “submit order” has been clicked and then check to see how amazon has divided up your shopping cart into separate fulfillments. Each will have a separate order# (this was a recent amazon change).

This will make it easier to have a 1-to-1 correspondence for later reconciling.

Btw, I’ve ordered from amazon since 1997 and they’ve never put an incorrect charge on my credit-card. I hope I didn’t just jinx myself by saying that.

By “their records” do you mean your Amazon “My Account” data, or the bank statement that shows the actual transactions that cleared the bank?

Is the total of your three amounts the same as the total of their severn amounts? If so, I would just rewrite my records to match theirs (that’s in fact what I do). That’s if you are anal about your bank records like me and you really want them to match one-for-one. Otherwise, if the totals do match, you can just leave well enough alone. As long as comes out in the wash, it doesn’t really matter since it’s just your personal checkbook.

If the totals don’t match, then you have more than just a bookkeeping issue.

I always use the amounts that are in the auto letter that they send with the amount … If I agree with that…

>see how amazon has divided up your shopping cart into separate fulfillments. Each will have a separate order# (this was a recent amazon change).

Ah! That would fix it, I guess. I will try that next time.
>By “their records” do you mean your Amazon “My Account” data, or the bank statement
I meant the bank statement, though I wasn’t being at all clear. Sorry.

>Is the total of your three amounts the same as the total of their severn amounts?

No. This was one of the combinations that I checked. I also checked the total of all their items on my bank statement with the sum of the first two items in my records, because the date on my third item is probably late enough it didn’t get included in the statement. I also had an ATM transaction on that date, and that didn’t make it onto the statement.
>rewrite my records to match theirs (that’s in fact what I do)
In all my previous statements I have been able to find several of my records whose sum is the same as several of their records. Then I’ll mark all of these cleared, both in my checkbook and on my paper bank statement. I’ll then write a note on the paper statement saying that these several Amazon transactions were grouped to match items in my checkbook. I don’t like to change items in my check records if they aren’t actually in error, but agree that it seems like one of the more reasonable options. In fact, wondering about how problematic this could be was part of my motivation for posting. My company, for instance, probably orders dozens of items a day from one of our vendors, with the items going to different coworkers in different plants grouped into different shipments, in a steady stream of business. I have to wonder how in the world they could ever make sense of it all.

> Subset Sum Problem

Hey, thank you for this. It’s a little pat on the back when I wasn’t expecting any!
>If the totals don’t match, then you have more than just a bookkeeping issue.

Well, I don’t have matching totals. I don’t have any interpretation of these things that agrees with all my information. Though, I think of that as a bookkeeping issue, because I have received all the items I think I ordered. I’m not sure if the ways things got grouped for shipping changed some of the charges, or if perhaps I entered something wrong, or they did. Of course, by changing the value on any one transaction, I can make everything agree, but that provides no assurance I won’t give myself an ugly surprise later.

I haven’t caught Amazon in any errors and do not imagine they are doing anything underhanded. Assuming they don’t make mistakes or cheat me, I think what I have probably is exactly a bookkeeping issue - some error on my part, or some combination I didn’t try.