Does anyone know if it is possible to have an amount deducted from an item total ?

For example:

If I list a computer system that includes a monitor, I want to be able to give the customer the option to remove the monitor and deduct a suitable amount from the item total.

The optional field is excellent for adding an amount to the item total... but can it be done the other way around ?

That is not a feature at this time but it is something we are looking into for a possible future update.

Excellent Scott

that addition, together with the coupon update will make it almost complete for me.

Keep up the good work !