Just curious. How do you send such cards? Still per post? Or per DHL....?
You're not going to like this answer because it's not useful to you but I send through a proxy. Being a dealer myself, both in comics and cards in the past, I had dealer friends who I could do that with but also people in the collecting scene in LA know, there is a crazy place called Frank And Sons warehouse and there was an official BGS grading booth I could submit to directly (now there is also a PSA booth there).
Frank And Sons warehouse is a trucking company where one of the "sons" started a gigantic collectors show...it's like several hundred dealers (of all sorts of nerdy collectibles), twice a week, free admission, free parking. And because there are so many dealers, I often pay just $5 over cost if I buy by the box or less if by the case. Sometimes those dealers are savvy enough to pick up decent product that there happens to be a glut of and other dealers/middlemen/distributors are dumping. I bought a lot of my Rookie Update for like $25 a box. That was the pre-breakers era. Nowadays I don't buy much hockey as I'm a bit jaded.
My advice is, find a really good brick and mortar store that has BGS and/or PSA account/s and after becoming a really good customer, submit through them. That's my advice in the US. In Canada you're kinda screwed...between the Canadian dollar, the distribution cabal, people on eBay not shipping to Canada, the Canadian Postal service and customs, you kinda just have to pay whatever their retail is, and hope they have a grading account to help you out.