Is KitKat uptake really slower than Jelly Bean was?

I fancied putting a few thoughts down after reading this article by Kevin Tofel based off a report from Chitika about Android platform distribution. The report suggests and Kevin writes about the fact KitKat adoption and uptake appears to be slower than with Jelly Bean according to Chitika's report.

My first reaction was that this can't be correct considering a number of manufacturers have pushed KitKat updates to their devices far quicker than previous OS versions, Motorola notably bringing it to their Moto X before Google had it on their own Nexus 4.

I had a quick look at the Android distribution numbers from Android Police and compared initial percentages for both OS versions.
Jelly Bean was released at Google I/O on the 27 June 2012. KitKat was released 31 October 2013 on the Nexus 5. Around 4 months later (121 days for KitKat, 127 for Jelly Bean) we have percentages from the Android developer dashboard. These run to 2.5% for KitKat and 2.7% for Jelly Bean which makes it look like initial uptake of Jelly Bean was higher but in fact this figure, being a percentage, fails to take into account the shear increase in Android devices in the market. When JellyBean was announced and released at Google I/O 2012 we had around 400 million device activations and when KitKat was released we had more than 1 billion activations.

If we take 2.7% of JellyBean at 400 million we get 10.8 million, compare this to 2.5% of KitKat at 1 billion we get 25 million. So immediately KitKat has a far higher number of devices running the new OS.
This all means that as a percentage measure of all Android devices KitKat is growing at a slighty slower pace than Jelly Bean but on a per device measure KitKat is growing exponentially faster. If you take the number of Jelly Bean devices activated and put that up against the 1 billion you'd have only 1.08% so actually KitKat has grown over 200% quicker, which pretty much shows that the answer to the question posed by this post is a pretty resounding no.

If we expand out to 150 days we get 5.3% for KitKat and 6.7% for Jelly Bean, but again looking at the assumed device numbers as per the previous calculation we have 26.8 million for Jelly Bean and 53 million for KitKat, again, a massive difference there and close to the 200% increase as per the 120 day calculation.

Images obtained from Google.
Gigaom article:
Android release dates:
Old OS distribution information:
Current distribution information: