Post History

POV is all about letting the reader see the things they want to see. One changes POV so that the reader can see things from a different angle. 

We often do this in life. We move around a scene so that we can see it from different angles. But there is a time for changing points of view and a time for maintaining a current point of view. 

When we change POV, we not only see things from a new angle, we cease to see things from the previous angle. If we are highly focussed on one thing, changing POV is likely to be highly distracting. But if we feel that we are missing some vital piece of information, we may be anxious to change our POV so that we get that missing information. 

This does not inherently have anything to do with how early or late you are in the book. It is about, do I, the reader, suddenly need to see things from this character's perspective in order to see things that are important to me? It may be that having seen most of the story through Gwendolyn's eyes, it suddenly becomes vital to the reader to understand how Reginald sees the situation. It will probably be uncommon to get into that situation late in a book, but it certainly could occur, in which case changing POV would be appropriate.