I know how to do addition in different bases, and I know how to convert between bases, but I have never heard of "adjustments" between bases while adding. I would solve this by simply getting a hexadecimal result and then converting it. But the wording is making me think that is not the intended way to solve it.
What is meant by this question? Is there some process I can follow as I go along to finish up with a decimal answer instead of a hexadecimal one?
Depending on the level of your course, the teacher or professor may be asking you to figure out how to do hexadecimal arithmetic with decimal points. See Fractional Hexadecimal Arithmetic
Beyond what you've already suggested the only "adjustments" I can think of are overflowing or carrying at 16 and leaving sums of A=10, B=11, C=12, ... F=15 (but 16=0x10) in one digit.