It seems unlikely that the K is locked in the OM...it just can't hold that much! A few ounces, sure. It didn't wash out. It didn't fly off and join the French Foreign Legion. Quite a bit is probably perking down, but...
Looking at last year's test and the differences, there are two possibilities. They're really looking inconsistent with each other, which might mean your soil isn't very consistent--or the sampling wasn't consistent (I hate to be accusatory, but...) I've found that, when I sample, I try to take waaaaaay more samples than they recommend. The last time, about 40 across the property, mixed together to get 2 1/2 cups, reduced to 2 cups that I sent.
If it's the soil, it may be that you want to send two different samples. I actually do that as well--my lawn and garden are very different soils and treated differently. It wouldn't make sense to send them together.
I'm reading this as a more-or-less pure test without overmuch considering last year's until after I do the read.
Phosphorus is great, calcium is high (and we'll take it). Magnesium is numerically showing a bit low, but that's deceptive and it's really not. I would love to shove potassium in the butt, but don't want to finagle your pH too badly since it's already a bit high and K won't displace Ca. The shortage isn't all that severe, we're in no hurry, and you're familiar with the process. Note that I shorted the level in September to avoid snow mold. [later note; after the 2021 review, I'm still keeping it this way, but if you move it to October and make it 2 pounds, I'm fine with that. I simply never make that recommendation north of the Pennsylvania/Maryland border. Ever.]
Post review of 2021, I see that Andy tapped your boron levels. I'm content with an 0.7 PPM level with a pH of 7.1, but apparently he has different standards.
If you wish to tap your boron levels at 3 tablespoons of Twenty Mules every 60 days, as in the Micronutrient Application Guide, I'm fine with that, but I'm not putting it in Recommendations. Grasses aren't particularly boron-sensitive. If this were a broccoli or cabbage garden, I'd have a much different answer for you.
Personally, I'm not in love with your soil's copper levels at that pH, but let's table that for this year.
Iron is OK for your pH, which won't generate the best color to begin with, but if you want to pour on the Milorganite or OceanGro or any other iron source, please feel free. Don't get spendy about it because, again, that pH isn't going to give much in terms of dark greens.
Recommendations:
April: Apply potassium sulfate at 2 pounds per thousand square feet.
June: Apply potassium sulfate at 2 pounds per thousand square feet.
August: Apply potassium sulfate at 2 pounds per thousand square feet.
September: Apply potassium sulfate at 1 pound per thousand square feet.
