[bitdivision]

Yes, an order of magnitude literally means 10x. But in my experience, in common speech it's often used to convey an approximation. i.e. 'Changing this will decrease performance of that endpoint by an order of magnitude', when it's really somewhere around 10x. If someone said 'decrease performance by 10x' that seems much more concrete to me.

[IncRnd]

Not exactly. An order of magnitude change doesn't always mean 10x in base 10! 15 and 150 differ by an order of magnitude but so do 15 and 180.