Applying some Buteyko breathing principles

I Came across Buteyko method online and while I'm not sure how to carry it out specifically, I am testing the idea that breathing less is beneficial for health. I  have been shallow abdominal breathing for 3 days now and have noticed benefits; more calm, warmer hands, warmer feet, find it easier to fall asleep etc. Will expand upon this more as time goes on. If you have any knowledge about this breathing method, e.g. know that it is wrong or right then please comment below.

I can't remember when I started this experiment, probably around 2 weeks ago, but I'm still not sure how to carry it out properly (a couple of books should arrive next week). However, I have been breathing through my nose completely and trying to stifle yawns, sighs and gasps. I can't really account for my CP but it seems to be around 35-45s at this point. When I started it was around 20s though my method of taking it has changed every couple of days. At first I breathed completely out before measuring it but later found another way of checking it which said to breathe out normally before checking. My CP is now 27s if I exhale completely before timing myself. So there has been definite testable improvement. Other improvements have included warmer body temperature, my hands are always the same colour as my arms which is nice considering that they used to always be cold and purple. I used to sleep with a dressing gown over the bottom of my bed and wear socks yet still have freezing cold feet. Now I no longer use either and my feet are almost the same temperature as the rest of me. I've been looking at the theory behind this method and sifting through every trial available on the internet and the general consensus seems to be that the theory is incorrect, but I've yet to see a single negative anecdotal report. In my view it seems that this type of breathing method is doing something... but no one seems to be sure what that something is. It certainly has some reliability in teaching diaphragmatic breathing in a way that definitely doesn't lead to hyperventilation. Some of the effects that I've experienced in the past week have been unusual for me, and almost definitely as a result of trying out this method. A few days ago I was so tired that I was barely motivated to move at all and slept for around 9 hours, only to wake up exhausted. Despite this I went out that night and stayed over at a mate's house, though I couldn't sleep the entire night. Normally if I do this I'll be tired the day after and barely be able to function, but this time I wasn't tired and stayed up until 5am the following day, even though I was trying to get to sleep for a few hours beforehand.

So, in summary, the Buteyko method, though done improperly by myself up until this point, has had noticeable effects despite my scepticism. However, I'm not sure why this has happened and the theory is under fire due to clinical trials pointing to lack of change in variables such as PaCO2 and lung function tests.