根据搜索到的关于分包商管理的资料：

6. Subcontractors:

• Quality of subcontractor work

• Subcontractor attendance at scheduled meetings and job site consultations

• Subcontractor responsiveness and compliance with contracting officer requests

• Subcontractor provision of appropriate manpower and material on schedule

• Validity and appropriateness of supporting documentation for change orders

所以我觉得Subcontractor attendance应该就是“出席之分包商”的意思，按1楼的解释，又是表格，所以“分包商签到处”应该也可以。