B777 First Officer reported concern and confusion over maintenance delamination limits involving two engines on two different airplanes.

Narrative

Preflighted a Boeing 777. Found deelamination on right engine. Called MX (Maintenance) and they eventually said it's out of limits. Got a swap to another aircraft and found more delamination of some kind on right engine as well. The left engine had some too but definitely not as bad. I'm not quite sure what the exact difference is between the two. The first engine is longer and maybe deeper but number 2 shows wider in some areas. Maybe not as deep? We just don't know really what to look for. Not sure how 1 is out of limits but 2 isn't. I'm skeptical of MX just saying op checks okay" and sending us on our way. The MX guy came up and showed us a reference on the second airplane but they ended up replacing the blade on the first airplane. So not sure what the technical difference is between both photos. They both look bad. The logbook on the first aircraft says the limit is .25x.25 inches and it was greater than that. The second aircraft looks greater than that as well but I don't know. As pilots we can keep calling maintenance to have them check as the company has mentioned multiple times to be more thorough on walk arounds."