Another expert here.............perhaps I can assist............................
"I do not feel that I can rely on the answer you provided because the instructions for Line 11 also state, "Note. If you have to apply another Code section that has a limitation based on taxable income, see Pub. 946 for rules on how to apply the business income limitation for the section 179 expense deduction." This sentence is prior to the section that starts with "Individuals" which states that you can add wages to the depreciation calculation, so I'm wondering if you have to be able to apply another Code section in order to add wages into the amount of depreciation that you can deduct?"
To respond to your above comment/question where your question is embedded:
"I'm wondering if you have to be able to apply another Code section in order to add wages into the amount of depreciation that you can deduct?"
The answer to that is definitely no. The comment you are referring to relates to another possible deduction subject to the income limitation, such as a charitable contribution, which is the example the IRS gives. It's not another code section to satisfy before including salaries & wages in the computation of the business income limitation. The example they give is a equipment expenditure of $520,000, and a charitable contribution of $20,000., with taxable income limitation of $520,000. If the maximum $500,000, 179 deduction is claimed, then the income limitation drops by $500,000., to $20,000. for purposes of the Charitable Contribution deduction. Since that is limited to 10% of net taxable income, the charitable contribution is reduced to $2,000., and $18,000. of the Charitable Contribution is carried over. (The other $20,000. of equipment would be subject to depreciation). So, it doesn't refer to any requirement for inclusion of Salaries & wages in the business income limitation.
Hope this helps clear it up for you.