If the Sales Summary Report does not match up to the Transaction Listing Report please look at the information below:
If you are comparing the Sales Summary Report and the Transaction Listing Report please make sure that you are looking at the same columns on both reports. The important columns have been highlighted in different colors below to show you how the data matches up between the two reports.
In the example below 1 transaction was recorded with an Item which was sold for $80, which was discounted by $20 from its original amount of $100 dollar sell price. Then $8 tax was applied to the $80 discounted sell price which makes the total amount of the transaction $88 dollars.
In the below sales summary report you can see the same numbers as above but the names of some of the columns are a bit different.
Below is an example of what would happen if you created another transaction on the same day but you did not re-save the Day End again.
If you compare the Transaction Listing Report above and the Sales Summary Report below you will notice some discrepancies in the totals. Above the total amount sold was $192.50 but below its only showing $88.00.This is because the day end was not re-saved so the Sales Summary report will not show the proper numbers. 
Please notice the yellow box around the * which is to the left of the date, this indicates that there was another sale that was done after the day end was originally saved. Also if the day end was not saved at all you will be missing this day on the Sales Summary report as well.