Hi Terri, temperature is an important factor, and even if you manage to keep it constante over time, the developer gets exausted over time, so you shouldn't be printing with the same time throughout your session.
The method I use is to develop my print 6 times the time it takes for the first image to show on the paper. Example: If you see the faint image on the paper 10 seconds after you put it in the developer, your development time should be 60 seconds. This is what I get with Dektol 1:2 with RC paper.
With FB paper I usualy get 2 minutes dev time when the developer is fresh and 2.5 to 3 by the end of my session. (12x16" prints... ;-))
You should also run another test, take the time your print takes to show the first image, expose a few strips of paper with a grey scale and process for 3, 4, 5, to 8 or more times your base time.
You will then compare them side by side, looking for maximum black buy paying attention to the whites as well, you don't want to overdevelop and get chemical fogging.
This test will tell you your multiplication factor (6 in my case), the tolerance (ou may be good from 5 to 7, 5 gets you full development and 7 isn't causing fog yet.
Hope this helps.