Workplace pension, auto-enrolment changes & 3520 confusion

Hello,

My query relates to a workplace/occupational/GSIPP pension and changes to auto-enrolment coming in April 2018 on minimum employer/employee contribution levels: 3% minimum of employees and 2% for employers.  My employer is paying the statutory minimum contribution.

I've been reading various sources articles which led me to believe that if my employee contributions exceed my employer's, my workplace pension will become a grantor trust and 3520/3520-A filing obligations kick in.

However, my US/UK tax advisor has simply told me that my situation doesn't trigger 3520/3520-A filing obligations but does not explain why. 

Before I press my advisors for chargeable advice on how they reached their conclusion, has anyone here stood by their position on this? Or have I confused myself over whether workplace pension is an employee's trust?

The 2 sources I read about 50%+ triggering 3520/grantor trust are:
newcomer link: http://www.buzzacott.co.uk/insights/how-us-citizens-can-make-the-most-of-uk-pensions-c [nonactive]
newcomer link: https://www.expattaxprofessionals.com/expat-tax-information-other-information-foreign-pensions/ [nonactive]

Thanks for any advice received.

You already have an accountant. Ask her/him which Section of the Internal Revenue Code exempts you from filing.

Shockingly, my advisor said, "please see 402(b)"

At this point, just assume I'm not relying on my advisor's advice anymore.  I've now also read §671 and §678 and I'm none the wiser on where to find the relevant reference about my pension contributions exceeding my employer's.

It sounds as if your adviser may not have directed you to the Regs: Section 1.402(b)-l(b)(6) https://www.law.cornell.edu/cfr/text/26/1.402%28b%29-1

Thanks Guya. I didn't realise such clear wording existed. 

I really hope my employer will stump up that extra 1% or else I will have to opt-out.  If I filed the 3520 & 3520-A the filing fees will cost more than my statutory minimum annual contribution.