Looks like in your first example you are using 415 V, and 230 in your second. The common convention is 415/240 or 400/230 V [lineline/lineneutral].
This is how I like to calculate:
First example: 22000/0.8 = 27500 VA. I = (27500/3) / 240 = 38.2. Same as your answer, just a slightly different way of calculating (and using 240 V, whereas 415/1.732 = 239.6 more accurately).
Second example: 7200/0.8 = 90000VA = I = 9000/230 = 39.1 A.
In your formulae using 1.732 x voltage assumes the voltage is lineline. In the second example, the voltage is lineneutral.
Hope this helps.
