So two questions. First if the two new fire skills give him 30% each like the other ones does that means he has got another upgrade to his sozin style firebending? The second is why only 1 level up? He has 32 plus 60 from the captain makes it 92. 92 plus 750 from the quest makes it 842. 842 minus 388 makes it 454. How much exactly do you need for the next level?
There is quite a lot of stuff one can do with firebending to make LIFE better... like: Keeping the soup/food/tea/milk hot all the time while eating. Heat up the bath, warm up the bed, roast meat.... To practice his control how about playing around with fire trying to create shapes? In a xianxia novel, the mc practiced creating houses, animals, fishes, until he could create a whole small town full of movement of people, animals, etc with so much detail that you could distinguish people's faces.