I'm also assuming that the Real Estate fee is an expense that I have to allocate to both the Asset and the Land
That's a perfectly valid assumption, and is not wrong at all. But keep this in mind.
your sales expenses on an asset actually reduce the taxable portion of your sales price. If the subtraction of those expenses puts the taxable portion of the sales price below the original cost basis of that asset, then you will have a loss on that asset.
Now it's weird, or at least seems that way. But if you want, you can put all of your sales expenses on the structure, if subtracting those expenses from the structure sales price keeps the taxable portion of the gain above your cost basis on that asset to allow for proper figuring of the taxable depreciation recapture. Your sales expenses for all other assets can be zero then.
There is no hard fast rule that you absolutely must allocate your sales price or your sales expenses proportionally across all assets. It's just that TurboTax has a "quirk" where in some cases (not all) it will not have the correct end result if you show a loss on some assets and a gain on others.
So when allocating, there's nothing wrong with showing a $50K gain on the structure, and a $1.00 gain on the land, along with a $50 gain on the roof. Then you show 100% of your sales expenses on the structure. But it is important that if you sold at a gain, you actually show a gain on all assets, regardless of the amount of gain on each individual asset. The bottom line end result will be the same no matter how you allocate, so long as you do it "my way" (for lack of a better phrase. :))
