You might have tried to do what I said but you still made a mistake which is why I wanted to see the code so I could see your mistakes and point out where you went wrong, and let you correct them. That is the way you learn.
Remember at school when you spell a word wrong the teacher asks you to write it down then times. That is an attempt to get you to learn spelling. By correcting your own mistakes you stand a chance of learning. By copying and pasting you do not learn anything.
So might that give you a hint as to why the LEDs did not fade in and out at the same times when you gave them the same voltages? Yes they we’re going in different directions but one was the complement of the other.