the cubed-method as in TOS (no upper limit), or the TNG method in which WF10 was the top (unreachable) limit in which if you did reach you could get anywhere instantly?
Yes in TOS the ship on it's own could not get above WF9, but there were episodes with help where they went up to 11 and even 14. In TNG 9.2 I think (I'll have to check or someone can say) is the highest for the ship, but 9.8 seems highest overall, and 10 is said to be unreachable.

