) and you have a concise webster on exactly why. M R, M K, P C, P M etc.etc. all the same. do the weights on written and guess what .... it performed to exactly the same number as it has when at 98.5% fit in the past. a ninth and a few portholes can indicate some sort of different form to a win .... but not necessarily a greatly different weight rating as the win. relativity and all that.