So I had asked Dev MattB about the Regular Shop Discounts vs Secret Shop Discounts. At this point with the Regular Shop Discount being basically a bug that is shared with all your team members, I'd say keep it that way forever. Personally like things that encourage players to work together, helping new players with say an experienced player going with someone that is new.
As far as the secret shop, make it like the regular shop, a global, team sharable discount. It just feels good to have discounts, without it, not having it shared feels like the bug.