Maybe DD's NRCS office didn't have to worry about the Corps and Tim's does, which could be due to either political OR topo reasons.
When I got planning help from the local Soil & Water office on my next pond, they checked and noted it was NOT on the Corps map as a wetland. I have the impression from both them and this forum that if it had a "wetlands" designation, Corps involvement would have been (much) more likely.