It's not about feelings, it's about contracts. Credit placement is related to how much money you make. Moving someone back in the credits means cutting their salary -- unless you stick them at the end with a "With/And Actor Name as Role," which is seen as prestige billing. (This is why Michael Shanks got such a last-place "as Daniel Jackson" credit when he returned to Stargate SG-1 after a season away. The actors after him in the credits had been bumped up in his absence, and it wouldn't have been fair to demote them when he came back.) By the same token, this is why Brandon Routh is billed ahead of Caity Lotz on Legends of Tomorrow, and why Victor Garber was billed first until his departure, despite having an increasingly small role. Credits are strictly about contracts and salaries, regardless of what happens with an actor's relative story prominence. The only times I've ever seen a new cast member inserted into the billing above an older cast member have been when the new cast member was installed as the lead, like Ben Browder on Stargate SG-1 or Bruce Boxleitner on Babylon 5. First I've heard of it, and it sounds like the usual Internet nonsense.