26 USC 6225 - Assessments made only after partnership level proceedings are completed

(a) Restriction on assessment and collection 
Except as otherwise provided in this subchapter, no assessment of a deficiency attributable to any partnership item may be made (and no levy or proceeding in any court for the collection of any such deficiency may be made, begun, or prosecuted) before
(1) the close of the 150th day after the day on which a notice of a final partnership administrative adjustment was mailed to the tax matters partner, and
(2) if a proceeding is begun in the Tax Court under section 6226 during such 150-day period, the decision of the court in such proceeding has become final.
(b) Premature action may be enjoined 
Notwithstanding section 7421 (a), any action which violates subsection (a) may be enjoined in the proper court, including the Tax Court. The Tax Court shall have no jurisdiction to enjoin any action or proceeding under this subsection unless a timely petition for a readjustment of the partnership items for the taxable year has been filed and then only in respect of the adjustments that are the subject of such petition.
(c) Limit where no proceeding begun 
If no proceeding under section 6226 is begun with respect to any final partnership administrative adjustment during the 150-day period described in subsection (a), the deficiency assessed against any partner with respect to the partnership items to which such adjustment relates shall not exceed the amount determined in accordance with such adjustment.