Hmmm. That looks interesting. I didn't know there was a ConditionalTotal function. Assuming this also takes care of the unique sku code (for say different) colours. Where would I place to get a total for each ID? Would it be in the calculation dialog like so...
IDQuantity = ($this->ConditionalTotal("Quantity","ID",$this->ID)) (I realise this might be a little out there)
Or does it goes somewhere else?