I'm not so sure it really matters what sim a company put you in for assessment. Perhaps many put you in an 'unfamiliar' type just see how you cope? They don't expect you to be able to handle it as you would an a/c you have a rating on, but perhaps they are looking at basic ability and your 'learning curve'. Do you fly the same profile three times and look just as bad on the last go as you did on the first? Can you assess your own performance correctly and demonstrate an ability to respond to training input? What's your CRM like? What excess capacity do you have when hand flying?
All these things can be assessed in any type and maybe an assessor gets a clearer picture of them all when you are under just a little more pressure due to never having flown the thing before. Possibly, but I suspect it comes down to cost and availability.
PP