Mega backdoor Roth问题请教

想Mega Backdoor Roth, 但不能in plan convert,也不能direct rollover. Does 60 days per year rule apply to mega backdoor Roth? 公司必须给我寄支票, 我去存Roth, 算indirect rollover. 但 IRS has 60 days roll over rule once in 12 months. 我一年只能转一次吗?(withdraw after 401K->Roth) 谢谢!