PayPal Standard Add-on, Form Total vs Amount Paid Variances

I have a registration form on a clients site that includes a base price of $50 with additional items being added via conditional logic (e.g. If “would you like a t-shirt” == yes, display t-shirt amount drop down selection. ) where a drop down is added if the customer selects yes. The values in the drop down are set to prices which are added to the total depending on how many are selected. (e.g. drop down item #1 = 1 additional t-shirt @ $15, drop down item #2 = 2 additional t-shirts @ $30, etc.)

Through all my testing I have not experience any issues, however 90 people have filled out the form and of the 90, 9 have a variance between the form total and the amount paid. In some occurrences where multiple additional shirts have been added, only the 1st additional shirt price is counted.

Another issue I’m experienced is it appears some customers have paid twice with two transaction ID’s appearing at the bottom of the customer entry. Please let me know if I need to add any more information. I’ve been trying to figure this out with no luck so far.

I recommend a support ticket for this issue: