Let price lists apply to regular external users (lingvists), not only Vendors

To use price lists for calculating translation costs we need use 'Vendors'. Using Vendors in the workflow has the drawback that once the workflow has started it's not possible to reassign a task. I.e. if the Vendor for some reason can't complete the task we're stuck. 

If we instead set certain regular users (Members) for a translation task we can reassign the task but not use pricing. 

Great if we could apply price lists to single users and have the ability to reassign. This would mean that price calculations is done again upon reassigning.