My take has been that unless there reads "raise this characteristic above 10" it can't go above 10.
Though in another POV, you may think they are above the 10 in case a spell or some such weakens the characteristic, but can use it only up to 10, just like
AS 1+ even though roll of 1 is allways failure in AS.
Also charges and marches do go over 10, depending of the Movement score. So maybe, just maybe, movement is an exeption?
Better play safe and ask what opponent thinks of it.