The Certificates I refer to are completely separate from proficiency - they're "add-on" exams / certifications from Grand Lodge that show you've learned the work 100% backwards and forwards. I think GLoTX now requires an A certificate for anyone moving up to WM.
I do have to say I love the formality of dress/uniform from the Scottish and English brethren that have visited my Lodge. Makes me feel way underdressed. :) One of the things I was told when first inquiring about joining was that "We care more about the man inside than their exterior, we're not going to reject or kick anyone out simply because they don't have a suit and tie or a tux. Wear the best clothes you've got, we'd rather you be here, period."
There's sometimes that I have to go straight to Lodge from work and I'm wearing shorts and a t-shirt - I get the feeling that would be scandalous in an English lodge (I do wear slacks and a polo shirt when possible).
We do now require jacket and tie for anyone participating in a part in a degree ceremony, though.
I love being the Secretary in an EA - we have a certain bit that's specific to Texas and Louisiana that I started adding a little flourish to, that's become tradition at my Lodge :D