Villager trade tables: Linear progression for librarians

At the moment, when using a workstation to assign a job to a villager, the trades are random and you have no knowledge of what trades will be available as their levels are unlocked.   

Please can this be simplified for librarians so when an enchanting book is offered as the first trade, it is always level one and as the villager levels up, it opens up higher tier versions of the initial enchantment.