I think the opposite would be true for the Maritimes.
If we held a proportional election without preferential votes, the Liberal Party would lose seats in the Maritimes. I don't know which ones or how many. If preferential voting was added, since the Liberal Party is the centrist party, I think it would lose fewer. But I haven't done any modelling, and I doubt that modelling would be entirely useful because people don't always vote the same way.
We can do a modelling exercise. It gives an indication, but it is very uncertain because people would understand very quickly how a preferential system works. The political parties that use it to designate their leaders wouldn't have any difficulty making their voters understand how it works.