Passing double cost of item to paypal

Hi
All my prices display fine on the website until they get passed on to paypal. If the buyer buys 2 of one product then paypal uses the cost of the 2 products for each individual product i.e item costs $200 , 2= $400 the cost in Paypal shows $800.

I think I caused the problem by sorting out this issue:
When an item is ordered and there are different options that cost more, the additional cost was displaying on the website but was not being passed onto paypal. I confess I fiddled with TotalPrice in the code that gets passed onto paypal.

So my original problem was the extra cost of options and currently that is working on the website but it has caused the problem at the top of this post.
In the hope that you can help I've attached the code.

Thanks for your time.

please post a link where i can see the problem.

the website is www.adrenalinr.com and if you try and purchase any muffler and change the quantity to 2 (as far as paypal ) this doubles the price.
For an example of an increase in price for an option go here productdetail.php?productID=518 and select the 101mm inlet size.

I've also attached my ecart1_php.php to see if that will offer some clues.
Thanks Jason

on the cart page, change the following code:

<input type="hidden" name="amount_<?php echo $eCart1_Index+1; ?>" id="amount_<?php echo $eCart1_Index+1; ?>" value="<?php echo WA_eCart_FormatNumber($eCart1->DisplayInfo("TotalPrice") - (($eCart1->DisplayInfo("Price")/$eCart1->TotalColumn("TotalPrice")) * $eCart1->GetDiscounts()), false, 2) ?>" />

to:

<input type="hidden" name="amount_<?php echo $eCart1_Index+1; ?>" id="amount_<?php echo $eCart1_Index+1; ?>" value="<?php echo WA_eCart_FormatNumber($eCart1->DisplayInfo("truePrice")), false, 2) ?>" />

Thanks Jason
This line produced an error:
<input type="hidden" name="amount_<?php echo $eCart1_Index+1; ?>" id="amount_<?php echo $eCart1_Index+1; ?>" value="<?php echo WA_eCart_FormatNumber($eCart1->DisplayInfo("truePrice")), false, 2) ?>" />

So I tried putting truePrice into the original in the place you suggested and it worked.
<input type="hidden" name="amount_<?php echo $eCart1_Index+1; ?>" id="amount_<?php echo $eCart1_Index+1; ?>" value="<?php echo WA_eCart_FormatNumber($eCart1->DisplayInfo("truePrice") - (($eCart1->DisplayInfo("Price")/$eCart1->TotalColumn("TotalPrice")) * $eCart1->GetDiscounts()), false, 2) ?>" />


Thanks again your help is really appreciated

glad to hear it is working.