=item 2.
-If a price is set from a source, it is read only. A price edited manually is by
-definition not a sourced price.
+If a price is set from a source then the system will try to prevent the user
+from messing it up. By default this means the price will be read-only.
+Implementations can choose to make prices editable, but even then deviations
+from the calculatied price will be marked.
+
+A that is not set from a source will not have any of this.
=item 3.
=item *
-A common complaint is that prices from certain vendors are always negotiated
-and should use a default value but must be editable (like free prices) by
-default. This should be orthogonal for all prices.
-
-=item *
-
The current implementation of lastcost is useless. Since it's one of the
master_data prices it will always compete with listprice. But in real scenarios
the listprice tends to go up, while lastcost stays the same, so lastcost