Over a 9x increase or almost a 10x increase would be just as dramatic and less mental effort and uncertainty to decode.
I think you've just proven OPs point. 10x is a 900% increase, or 1,000% of the original price, not 1,100%.
Using percentage for anything other than a fraction of something (i.e. <= 100%) is usually done for effect, often done incorrectly, and even if done "correctly", leads to exactly this kind of confusion.