I would guess that your OM is still there. You just mixed it all up. Take your bucket example. If you filled your bucket 75% full with low ph soil, then topped it off with a neutral ph soil. Then you mixed it together. The neutral ph soil is still there, but won't show up as high on your soil sample. Just because you cut it in doesn't mean that it's gone as soon as it's cut in.
That thinking might work N2T if there wasn't such a thing a decomposition. But unfortunately, organic matter has a shelf life and that depends on how you manage it. The soil tests then showed 0.5% OM....the soil tests now show 3.5% OM (or there about, I forget the exact number right now) The CEC or holding capacity then showed 2.1....now its 5.9.
Was your %OM just taken at the surface?
It's not decomposing in a years time. Our CEC is going up, also.
