Baby Bearded Dragon not growing fast enough

Hello, my bearded dragon, Jervus Jean, is about three and a half months old, weighing in at 48 grams. I have had him (or her) for about two and a half months and he has not shed. I offer him dubia roaches, black soldier fly larva, and silk worms (all smaller than the space between his eyes). I offer him as many bugs as he wants but he only eats 10-15 a day (sometimes more or less). We dust his bugs with calcium five times a week and multivitamin twice a month. I also offer him collard greens and bell pepper every day with occasional fruit, but he has only eaten a little salad since we got him (hand fed). He has a basking spot at 105 degrees and cool side at 78 degrees. His UVB is Reptisun 10.0 T5 HO that covers 3/4 of his tank. The furthest he is from it is 47 cm the closest he can get is 24 cm. His substrate is non-adhesive shelf liner. He gets up at 8:30 am and eats breakfast at 10:30 am. He has dinner at 5:30 pm and goes to sleep at 8:30 pm. I offer him water at both of his meals and he drinks it sometimes. He usually takes a nap about half an hour after his dinner. I don't think he has parasites because it does seem that he has bulked up a little since I have gotten him, and he has gotten a vet checkup when we first got him (but no fecal exam). I have tried Repta-Boost but he did not like the food or experience at all. Do you have any tips to get him to eat more or shed?

Dragons grow at different rates-- do you have a reflector on your UVB and where in the tank is it? Top of screen or inside the tank? I would mix his salads up offering different greens here is a website for nutrition ignore the kale thing its a great staple feeder http://www.beautifuldragons.com/Nutrition.html
Is there a distance in between for the UVB -- 24cm is too close and 47cm is too far -- distance should be 12-15 inches directly above the basking decor piece if its inside the tank ---

Thank you for your quick response. His UVB is mounted inside the tank with a reflector. He has lots of decor on the ground that makes him 4-7 inches closer to the UVB, and a climbing tower with several levels varying in distance from the UVB (the closest level gets him 24 cm away from the UVB). I have been finding my lighting distances off of the ZooMed lighting guide. From my understanding 24 cm is the closest it can be for it to be safe, and 47 cm is the furthest away it can be to still be effective. Please correct me if I'm wrong or if you have any other suggestions. Thanks again!

You don't want that UVB any closer than 12 inches and no farther than 15