Not sure if they send impressions back and I don't know how much they would charge you for shipping to get back if you need a refit. Btw when I shipped my impressions to them I just did basic parcel post and it cost like $3 and made it in like ~10 days. When they ship it back it's obviously not overnight (coming from China would probably be damn near impossible lol) but it does get back very quickly and it's from UPS with tracking. As far as recessed sockets, maybe you could ask if they would do them?
To avoid having to pay shipping again for a refit, just make sure your impressions are perfect and hopefully you won't need one! I took my own impressions for 2 reasons, 1) the kit cost $20 for 5 tries and the cheapest impressions around me were $40 per ear & 2) I trust myself with multiple tries more than a one try expensive impression from someone who possibly has little to no experience doing impressions for CIEM's. People generally advise not to do your own impressions though because you could damage your ears if you mess up.
Edited by Aaron1006 - 6/6/12 at 12:08am