Unless the contract includes a specific air sealing measure or spray foam insulation, then no air sealing improvement can be claimed in TREAT. Windows and dense packing by themselves do not count as air sealing.
Enter air sealing for the unconditioned areas as an infiltration reduction of the heated space, not an ACH reduction in the unheated space.
Check the proposed air sealing target to make sure it is not below 70% of the minimum ventilation guidelines or BAS. If the house is made too tight, then mechanical ventilation will be required.
If you are not able to achieve the target CFM50 number, then the SIR may fail at test-out.