When I view the Sales report (Reports->Sales), it tells me I have 22 orders and made over $1000. When I view the orders (Sales->Orders), there are only 15 orders and I made a lot less.
Also, the dashboard only shows $737. Where are all these numbers coming from?
I'm using Magento 1.4.0.1.
To the best of my knowledge the main discrepancy between the totals is the tax, shipping, cancelled orders and refunds. The dashboard lifetime sales shows an amount that reflects all orders less tax, shipping, refunds, and cancelled orders. Not sure what the difference in your total number of orders is but I'd assume it has something similar to do with the number of cancelled, pending or refunded orders. This is just a theory and I'm not positive this is how it actually works, but when I've done the calculations it all seemed to add up in our stores give or take a few dollars. Hope this helps!
I've just verified that the reporting ignores the Timezone setting under Locale options (Admin > System > Configuration > General) when considering the order's creation time.
Order creation time is saved in the database according to GMT, and it is that value that is used when grabbing orders for a particular range. To wit: If your store is PST (-7 GMT), then an order placed at 5:13pm PST (17:13 PST) on July 1 will be saved in the database as 12:13am GMT (00:13 GMT) and included on the report for July 2; all of this despite the fact that the order shows as having been created at July 1 @ 5:13pm when viewed in Admin > Sales > Reports.
While I believe that storing times in the database as GMT is absolutely correct, I believe that the reporting should honor the locale setting, given that it is used everywhere else.
I've added this info to Bug Report #23110, which is viewable at http://www.magentocommerce.com/bug-tracking/issue/?issue=9196