Do T&M CLIN(s) require a period of performance even if funds may burn out prior to the expiration of the PoP? And if funds do run out, are we not expected to receive a Limitation of Funds Notice, which we than can determine if we can add additional funding?
1) Yes. FAR 4.1005-1(c) states:
"Each deliverable line item or deliverable subline item shall have its own delivery schedule, destination, period of performance, or place of performance expressly stated in the appropriate section of the procurement instrument (“as required” constitutes an expressly stated delivery term). When a line item has deliverable subline items, the delivery schedule, destination, period of performance, or place of performance shall be identified at the subline item level, rather than the line item level."
Using the "not sure when the money will burn out" logic would also exempt cost reimbursement type contracts from having to include a PoP. We know that's not the case.
2) Whether or not a limitation of funds notice is required in your situation is specific to your agency's (SEC's) internal procedures and I cannot comment on that.