Its hardly ever consistant and I would be surprised if writers or editors pick up on it unless its obviously noticeable. For example the Thing is supposedly 6ft which is actually shorter than Reed Richards and would make him amongst the shortest elite Marvel strongman yet apart from the Hulk do you ever see many other heroes tower over him?
Other examples where no one seems to notice the difference in characters heights was when you have the 5'9" Bucky replacing the 6'2" Steve Rogers as the new Captain America yet no one notice that he was far too short to pull it off? Same thing happened over at DC when tiny Dick Grayson replaced the far taller and far muscular Bruce Wayne as Batman and no one could tell it was a different guy because he was drawn exactly the same.
...as I stated, they had a graph showing Cage at 6'2 and Brashear at 6'6. This wasn't artistic license.