Question 1:

In accordance with FAR 15.403-4 (a)(1)(iii), if the absolute value of the ceiling increase modification exceeds the Truthful Cost & Pricing Data Act (formerly known as Truth in Negotiation Act (TINA)) threshold of $2M and an exception does not apply (FAR 15.403-1(b)), certified cost or pricing data is required for your modification.

Question 2:

The FAR reference that you noted is correct.  If your modification exceeds $2M and an exception listed in FAR 15.403-1(b) does not apply, a waiver would be required if you will be relying on other than certified cost and pricing data.   FAR 15.403-1(c)(4) states “(4) Waivers. The head of the contracting activity (HCA) may, without power of delegation, waive the requirement for submission of certified cost or pricing data in exceptional cases. The authorization for the waiver and the supporting rationale shall be in writing. The HCA may consider waiving the requirement if the price can be determined to be fair and reasonable without submission of certified cost or pricing data. For example, if certified cost or pricing data were furnished on previous production buys and the contracting officer determines such data are sufficient, when combined with updated data, a waiver may be granted.”