I never said it would be efficient.
And if we were to take the base price offered by the Ore terminals (essentially the minimal material price), always rounding up to full stacks:
14x7620,48=106686,72
10x3787,41=37874,10
8x9797,76=78382,08
7x544,32=3810,24
7x870,91=6096,37
7x4354,56=30481,92
7x979,77=6858,39
6x10886,4=65318,40
5x8709,12=43545,60
4x2503,87= 10015,48
2x4354,56=8709,12
1x816,48=816,48
Sum=398594,90
If we excuse the 10k difference to be caused by always rounding up, you get pretty much the price you'd get at the terminal.
It is not efficient, but you are at least guaranteed some return.