Premature Distribution Penalty applicable to distribution from Disqualified Plan?

[Guest Pennysaver]

Hypo:

Plan is disqualified. Plan subject to taxation retroactively for all years. Previous distributions from plan were made as direct rollovers to IRA. Due to disqualification, rollovers now treated as excess contributions to IRA. Because previous distributions from disqualified plan no longer constitute eligible rollover distributions, IRS states distributions are subject to 10% early withdrawal penalty under IRC 72(t).

But:

IRC 72(t) specifies the 10% early withdrawal penalty is applicable to premature distributions from qualified plans. Does any other authority provide that this penalty can be imposed on a premature distribution from a disqualified plan?