I think its normal. Its take a little getting used to. Keep in mind that mirrors are just another tool. Not only do I use Cipa mirrors, I use 3" convex mirrors on the corners of my truck mirrors. That's 3 different views!
With your trailer hooked up and sitting parked, just look at each of your 4 mirrors for a little bit and get used to the view they provide. As you drive, try not relate the view of the mirror extensions too much, you'll have to look at them for a few seconds longer than you are used to. After a while it will become second nature and you'll only need a glance to know what's going on.