It's odd that you refuse to accept two perfectly valid mathematical ways to show that one number has grown by 34.6%. The rise in the rate of inflation has increased by a 1/3rd. You cannot dispute this.
You cannot calculate the rate of inflation like that. Inflation indicates the change in prices, as a percentage, over a set period of time.
What you are referring to is the Rate of Change, But for inflation, there is no such calculation. Never has been, Probably never will be because inflation is measured in the change in prices, from the beginning of one period to the end of another period.
You cannot use the inflation rates themselves to calculate some other nebulous concept.
To draw you an analogy that you might understand:
You can measure the heights of tides, and compare one day's height with another days, to see the difference as a percentage.
But then taking two percentages and trying to draw some inference from it would be nonsense.
It might give you a rate of change, but that is useless to man and beast, because it would vary so much from time to time, season to season.
Instead of a line graph showing the heights of the tides per day, you would end up with a grossly exaggerated swings of percentages, which would not represent anything, and would be useless anyway.