In another case, there were monthly invoices received from an accountant for accounting charges of Rs 2500/= per month. But the Enforcement Officer treated it as being liable to PF. He took the view that an accountant is not a professional like lawyer or CA, and so his fee is not professional fee, but only a salary for his services. So he created demands for many previous years on this premise treating the accountant as an employee. I do not know if he was right or wrong in that case.
But if there is no monthly payout, just an annual invoice in March, of an amount more than the threshold of PF, then it should certainly be out of PF.
If you want to come out of such hassles, you can also ask the accountant to raise an annual bill. But I would not recommend such an action because an accountant working independently who take the work of other companies along with yours is not an employee.