FAQ Orders

What is the difference between regular, priority and urgent orders?
What does "unplanned" mean in the RTS review date (order follow up details)?
RTS dates are sometimes exact and sometimes estimated: is it possible to have information on the accuracy of an RTS date?
When are the goods invoiced?
Technical orders... I check carefully codes to avoid or at least reduce the possibility of technical orders, yet there are still unavailable items. When I check the codes are available in the catalogue but are still split in a technical order...