A rating by any other name would smell as sweet... as the saying goes - I think.
ERA, oiler, I believe is still the same thing in Canada, deep sea is another thing, but here the experience counts as the same.
Anyways, I am not sure if you drop by the training page at all, it pretty much has the answer you seek. Or at least I though it did. There has been some changes to the regs, and I am working through updating that page, but I believe it is fairly accurate, including information on the "alternate path" check out the Mallaspina PDF file on the training page - in regards to your experience and the stuff TC wants out of you.
If you have drop by that page and still have questions, please fire them off to me, and I will correct the lack of insight. Don't forget to download your Sea Time testimonial sheet in pdf - fillable format from the machinery page. Mmmm. that remind me, I should really put it on the training page too.... I will do that.
Cheers, and welcome to the coast.
Certified Marine Engineer and Webmaster
Martin's Marine Engineering Page