Just added tickets this morning. No problems encountered. Quoted price matched the calculator with no issues.
One oddity was that the CM needed to know where the "conference" was being held. She said she couldn't process without listing the location. I told her I was staying at French Quarter (even though we're doing a split stay between the group rate at POP and a CM rate at French Quarter), so she decided to mark down Coronado since it is the one Moderate-level conference hotel. A bit weird, but she assured me it would have no effect on me.
Three tidbits:
1. Ordering the park hopper option, the CM gave me the park hopper plus ticket (with one plus option). I assume this is standard for the group, but I didn't see it written anywhere. Probably won't use it, but it may add significant value for some!
2. You can only use a max of 3 gift cards to pay for tickets. The CM was really nice about waiting on the phone while I merged my cards (and while I figured out even how to do that!), but you may wish to consolidate cards at disneygiftcard.com before calling. When you pay off a reservation (via phone or in person), you shouldn't run into this issue, but merging might still be a good idea since it means fewer numbers/cards, a faster transaction, and refunds back to one card instead of several (just in case).
3. Tickets expire 14 days after first use, are not refundable, and must be first used by 12/31/2017. (Not 2018 since these are in a way 1 year old tickets already). Won't matter for most of us, but it's good to know all the same.