Hello, this is an url:
http://www.agriprotector.com/es/tienda/ ... -50-detailIn the last version of Virtuemart, when a product is on sale by multiplo, the buttons + - are working with multiplo of sales pack. For example, in this case the product is sold on packs of 400 Unities and the buyer must buy multiplos like 400: 800, 1.600, etc. The buttons + and -, charge or leave 400 unities each time that the user click on a button. For us is very good to use these buttons in our web. Excuse my English.
Thanks and Kind regards!