There is no difference.
In terms of the vote, the Chief Electoral Officer tallies the votes the same way as he does now. In converting the result to the number of MPs, he considers all the votes cast. I will not go into more detail about the algorithm, but it is a formula used to balance the matrices. For example, there must be enough Liberal MPs in order to have proportional representation. For the Liberals, for example, the person with the most votes gets a ratio of 1. The Conservatives, who placed second, get a ratio of 1.2. For the NDP, the ratio is 1.27, and it is 3.32 for the Green Party. Then all the local elections are calculated. It could happen that the party that places third in a constituency is ultimately elected. That is the unpleasant part, from a psychological point of view.