DFARS 219.201(c)(10)(A) reads as follows:

"Contracting activity small business specialists review and make recommendations for all acquisitions (including orders placed against Federal Supply Schedule contracts) over $10,000, except those under the simplified acquisition threshold that are totally set aside for small business concerns in accordance with FAR 19.502-2. Follow the procedures at PGI 219.201 (c)(10) regarding such reviews."

I can understand your confusion because this is worded awkwardly.  It might help to think of it this way: If the acquisition is between $10K and the simplified acquisition threshold (SAT), and this IS a small business set aside, the DD form 2579 is NOT required (but also read PGI 219.201(c)(10) for further clarification).  However, if the acquisition is between $10K and the SAT but it is NOT a set aside, then the DD form 2579 IS required.  Finally, regardless of whether the acquisition is a set aside or not if it is over the SAT, then the DD form 2579 is required.

Hope this helps.