I bet you are not getting everything out of the bar groove if you're actually cleaning it out! I get ahold of bars on chainsaws that I buy, that I am positive that nobody ever scraped the crap out of it like it needs to be done! And that stuff gets packed in the bottom of the groove so hard that I have to get medieval with it to get it to break loose! A hack saw blade works pretty well if you run it through it a couple of times like you really mean it! And once you get it all cleaned out,
make a habit of pulling the bar off the saw every two tanks of fuel and flip it 180 degrees and run your hack saw blade through the groove in the bar so it doesn't build up until you have an issue with it. Think about it like this, that is how the bar oil gets distributed to all the links in the chain is that groove in the bar! So if I were to see smoke coming from the bar and chain areas that would be the first place I would take a peek at and eliminate that as a culprit of your smoke! I think you will find that to be the problem nine times out of ten for an oiling issue.
I have to disagree with your instruction, You only need to flip the bar every time you install a sharpened loop and far as cleaning the groove and oiler holes, when you change the loop, clean it and I use an expired credit card to clean mine and I clean out the oiler holes at the same time as well. After I clean it and renew the loop (if I'm in the shop, I'll take my air blow gun and run the length of the bar to make sure all crusted in swarf is removed. If the roller nose has a grease port (all my Echo's do as well as my old 028 with the Carleton bar, I'll grease the roller nose with a grease gun with a needle tip installed or with a specifically designed bar nose greaser which are available at any saw shop or online at Fleabay or Amazonian. When the bar is off, clean the oiler holes out as well.
I prefer a greaseable roller nose but that is a subject for another time and always use bar oil, not drain oil or used any oil. Bar oil is tacky and won't fling off as the chain loop rotates. I get mine at Menards or Lowes when on sale, cheaper than the local saw shop and lots cheaper than a Stihl dealer by a long shot.
Side note, the Oregon depth gauge tool will have a tapered end that is ideal for cleaning the groove out with,
Finally, what the sawyer in the video stated about the bar being flat is also incorrect. That bar has to have a rock to it across the entire length from just behind the roller nose to the oiler holes. Flat don't work, the bar is shot the channel must be of a consistent width and retain the drive tangs somewhat loose but not too loose. The coin track works quite well actually and no burrs on the outside edges of ANY bar, that is very indicative of an overheated bar as well as the powder coated paint flaking away from the bar edges along the chain run which can also be indicative of running the loop too tight and that also robs engine power, wears the drive sprocket out quickly as well. ALL drive sprockets whether clutch drum mounted or spindle mounted have maximum wear marks stamped into the sprocket face. When the wear nark is realized, it's time to replace them. A worn drive sprocket will not engage the drive tangs on the loop properly and the decreasing radius of the sprocket causes the drive tangs of any loop to bind and reduces power to the loop, appreciably. I always have a couple in the shop on the shelf at all times anyway. Save a trip to the saw shop or buying online and waiting for them.
What I do if I flip the bar in the shop is, I take my blow gun and blow out everything on the powerhead including the cylinder cooling fins and drive side as well as the air filter and from the inside out on that and with reduced air pressure, but than I'm somewhat anal about clean saws and my ag tractors as well and even the engines and underbodies on my vehicles. as all my hay implements as well.
Just how I roll and have for 50 years.
Different folks approach it in different ways. I have my regimen, it works and I'm good with it. Been using chainsaws since they had 4 stroke engines on them and in retrospect, I wish I had kept some of them as the antiques are worth some jack today. I didn't however, stupid me.