Section 271 b for audit under 44ad

In my opinion it will apply. Let's understand why:

The law lays down levy of penalty in two circumstances i.e.

for failure to get his account audited; or
for furnish a report of such audit as required under section 44AB of the Act.

Let's understand what section 44AB requires:

Audit of accounts of certain persons carrying on business or profession.

44AB. 32Every person,—

(a) carrying on business shall, if his total sales, turnover or gross receipts, as the case may be, in business exceed or exceeds one crore rupees in any previous year ; or

(b) carrying on profession shall, if his gross receipts in profession exceed [fifty] lakh rupees in any previous year; or

(c) carrying on the business shall, if the profits and gains from the business are deemed to be the profits and gains of such person under section 44AE or section 44BB or section 44BBB, as the case may be, and he has claimed his income to be lower than the profits or gains so deemed to be the profits and gains of his business, as the case may be, in any previous year; or

(d) carrying on the 34[profession] shall, if the profits and gains from the 34[profession] are deemed to be the profits and gains of such person under 35[section 44ADA] and he has claimed such income to be lower than the profits and gains so deemed to be the profits and gains of his 34[profession] and his income exceeds the maximum amount which is not chargeable to income-tax in any 36[previous year; or]

37[(e) carrying on the business shall, if the provisions of sub-section (4) of section 44AD are applicable in his case and his income exceeds the maximum amount which is not chargeable to income-tax in any previous year,]

Thus it can be said that 44AB, also covers cases where Audit is required under section 44AD. Therefore, penalty u/s 271B shall apply.