Are these people you've only met in the last few minutes because a few hours ago you said they probably didn't need lengthening but it should be done for uniformity?
Apologies, my post wasn't as clear as it should have been. The question that was posed was if VT needed all of their trains to be 11-coaches long. And my answer was no, they don't
need all of their trains to be 11-coaches because there are some services which aren't full. Indeed there are some services where even a nine-coach train is overkill. Not to mention the fact that loadings vary along the route.
However, since some of their services need 11-coaches, it would be sensible to make all of their trains 11-coaches since the marginal cost of running a couple of extra coaches on services where they aren't required is more than offset by the potential losses caused by only having 9 coaches where 11 are required and the operational flexibility that a uniform fleet provides. This also caters for potential growth.