I think of buffer pH as the size of the cup you are filling.  If you have a 5.5ph on really heavy high cec dirt, it takes tons and tons of lime to get up to 6.5 or 7.0.  That buffer pH may be 6.4, the lower the number, the more lime it will take to neutralize.

On the flip side, if you have a 5.5 pH on sands, it may only need 1000lbs to get it up to 6.5ph, and the buffer pH will show 6.9 or 7.0.  A lot of these numbers are formulas from a combination of pH, base saturations and CEC.  I think that is where a 7.2 comes from, it definitely  needs calcium/ magnesium/ lime, but just in very small amounts, if you overdue it you could push a lot of other nutrients off from the very small cation holding capacity.

Many of the recs also only adjust to 6.2 pH, I always adjust to higher pH and that will increase your rate.

Regarding the P and K testing.  Im somewhere in the middle of you never need fertilizer and you have to fertilize for crop removal every year.....lol.