I'm not a lawyer, but it looks like the penalty for any number of violations of 31 USC 5324(a)(2) is the same.
Hastert can be ordered to "forfeit all property, real or personal, involved in the offense and any property traceable thereto" and he can be fined up to the dollar amount of the transactions (minus the amount forfeited). So, Hastert can be fined up to $952,000. The number of transactions doesn't seem to affect the penalty.
§5317. Search and forfeiture of monetary instruments
(c) Forfeiture.—
(1) Criminal forfeiture.—
(A) In general.—The court in imposing sentence for any violation of section 5313, 5316, or 5324 of this title, or any conspiracy to commit such violation, shall order the defendant to forfeit all property, real or personal, involved in the offense and any property traceable thereto.
(B) Procedure.—Forfeitures under this paragraph shall be governed by the procedures established in section 413 of the Controlled Substances Act.(2) Civil forfeiture.—Any property involved in a violation of section 5313, 5316, or 5324 of this title, or any conspiracy to commit any such violation, and any property traceable to any such violation or conspiracy, may be seized and forfeited to the United States in accordance with the procedures governing civil forfeitures in money laundering cases pursuant to section 981(a)(1)(A) of title 18, United States Code.
§5321. Civil penalties
(a)(4) Structured Transaction Violation.—
(A) Penalty authorized.—The Secretary of the Treasury may impose a civil money penalty on any person who violates any provision of section 5324.
(B) Maximum amount limitation.—The amount of any civil money penalty imposed under subparagraph (A) shall not exceed the amount of the coins and currency (or such other monetary instruments as the Secretary may prescribe) involved in the transaction with respect to which such penalty is imposed.
(C) Coordination with forfeiture provision.—The amount of any civil money penalty imposed by the Secretary under subparagraph (A) shall be reduced by the amount of any forfeiture to the United States in connection with the transaction with respect to which such penalty is imposed.