OK, I'm not going to claim the be the expert here nor have read that article in detail but there are 2 things to consider, peak current and average current - the fact the current is said to increase in the article makes me believe it refers to the latter.
Below is picture of the current in an ignition coil. Being an inductor, it takes time to reach a peak (remember your post about resistance of coil and current) , then the ignition module still supplies power (max current possible is limited by coils resistance) in order that at every rpm, the spark has the same energy.
So the peak current is the same across rpm range but average current increases with the rpm.
Actually you can determine the peak current by measuring the coil resistance, from memory original coils are circa 3 ohm, COPs around 1.5 so that gives 4.6 and 5.3 Amps (using 14v as max voltage input).