eddie: your second session looks like you got a better result. Old Brown does make a difference. I use LD20 as well, but I print on Foma Classic 131 paper. I am using 20ml of A to 20ml of B to 600 ml of water at 30c, and then topping off to 1 liter with old brown. This formula is giving me the nice, bright, salmony tones that I like. I know that this is contrary to what the directions say to mix each concentrate separately with water then mix together, but I did that by accident once after using another brand with a different mixing scheme and it worked, so I stayed with it. Also, unless you have run several prints through the developer it may not be as dead as it should be. After a session I always leave my developer in the tray overnight to oxidize, and if I had not run many prints through the developer I throw an old sheet of paper in the developer to really kill it. Then next day bottle it up and I am good to go.
Unless you like the sort of thick, dense image that you are getting, I would recommend backing off on the exposure a stop or so to brighten the highlights and improve the contrast. Your shadows will develop to the desired density with time. If your highlights don't develop enough you know you backed off too much on the exposure. I fight with a cool darkroom in the winter as well, and find that I can keep my developer warm by covering it with a clear sheet of acrylic. I aim to keep my developer at 30c and usually get a print between 3:30 and 5 or 6 minutes, depending on how old the developer is.
Best of luck,
Dan