Hello Sally5432,
I checked my test lab, which holds the same PMImport v7.1.483, and found that the Software Update Policy created is in order with the proofloc2010-KB2760781-fullfile-x64/x86-glb.exe update listed on the Advanced tab.
Perhaps you have an exclusion for this software in place on the Vendor Listing > Software check box under the PMImport > Vendors and Software > Microsoft > Office or Proofing Tools 2010 settings.
If these are disabled; re-enable them and re-run the PMImport with Incremental download enabled. This should bring down the previously disabled updates.
Note: The PRC should display about 8 updates for English only for MS13-091.
Let me know if this helps,
Joshua