My 2 story brick colonial was built in 1942. The upstairs is hot in the summer and cold in the winter. There are 3 bedroom and 1 bath upstair. The master bedroom is the room that is always the most off in temperature. It has two register in the room, directly across from each other at the baseboard. If I took one register and moved it higher up on the wall and then reconnected in the basement as a return, would that help? Here is a picture of the upstairs. The green blocks are vents and the red blocks are returns. The 2 returns are connected as one and is way undersized. Thoughts? The furnace and ac are within 2 years old, properly sized for the house and are 98% efficient units.