It's too bad you were given the wrong info on those dangerous bulbs because he could have had one now for a couple of wks and could be doing better now.
Petstores are known for giving wrong info. They don't research beardies like we have & don't have the experience.
You mentioned that you have good temps, etc. Could you give me a rundown of the setup and what you're feeding? I know you said you were using a digital thermometer but does it have a long wire with a probe on the end? How often are you dusting the live food with calcium & vitamins? What type of substrate are you using? Babies are very particular with their needs so want to make sure everything else is fine except for the UVB of course.