the entries that I input for "sales price" for the sale of the structural asset itself PLUS every improvement should total $226,800. Correct?
yes, that's correct. Since you sold at a gain, it's important that you show a gain on each asset. Otherwise, depreciation recapture will be wrong, potentially resulting in you paying more taxes than you should.
Now when you add that total sales price of $226,800 to your sales price of the land, that total should be #315,000. If so, you're good to go.
