Ahah - I understand.

The are two lots of 'prices' in the system - what you sell things for and what you pay for them when purchasing them.

See http://www.openvpms.org/documentation/csh/1.8/concepts/pricing - part of which says:

"When you are setting the price, you can provide an ex-tax cost price and a markup percentage, and the system will calculate the resulting tax included price (as (C x (1 + M/100)) x (1 + T/100)). Alternatively, you can set the tax-include price over-riding any cost and markup."

So the sell price can be linked to the cost price.  But as you say, different suppliers charge different amounts, and their prices may change.  As you will see from http://www.openvpms.org/documentation/csh/1.8/concepts/pricingUpdates you can make use of the system's auto price update feature.

So - when you fill in the prices on the product's Pricing tab (see http://www.openvpms.org/documentation/csh/1.8/product/tabs#prices) and set the cost price, this is not dependent on the supplier's nett and list prices set on the product's Supplier tab (see http://www.openvpms.org/documentation/csh/1.8/product/tabs#supplier)

However, when you finalise a delivery of a product from supplier xxx AND that product's supplier tab for supplier xxx has Auto Price Update set, then the cost price and the resultant selling price (on the Prices tab) will be updated.

Similarly - if you edit the List price in the Suppliers Tab AND the entry has Auto Update set, then the Cost Price in the Prices tab will be updated.

So to answer your questions:

1) the system will only generate orders from the preferred supplier.  You can of course manually create an order from a non-preferred supplier.

2) when  the delivery is finalised, whether or not the Cost price gets updated depends on whether the Auto Price Update flag was set for the supplier from whom the goods were ordered.  Hence the "normal" setup is to have Auto Update set for the preferred supplier, but not for the non-preferred supplier(s).  Hence, if you every have to order from the non-preferred supplier (say because your preferred supplier has no stock) then the non-preferred supplier's prices will not be used to update the cost prices.

3) the same Cost Price update occurs if you manually update the List price in the Suppliers Tab, AND Auto Update is set - this is documented in http://www.openvpms.org/documentation/csh/1.8/product/tabs#supplier where it says:

Hnce I would avoid setting the Auto Price Update flag for suppliers other than your preferred one - so that when your non-preferred supplier says "we are increasing the price to $$$$$" (and you think - humm thats why they are not my preferred supplier) and you go enter the new list price from that supplier that you DO NOT update the cost and sell prices.

Hope this helps.

Regards, Tim G