Yes, that is what my point was to the OP - first of all, is it actually a true SDC or did they waive a change fee based on a restrictive fare? If SDC isn't allowed on the AC fare rules, then it means it's a change fee to confirm onto an earlier flight. A TA may or may not have their own change fees when changing to an earlier flight regardless of the airline's fare rules, so I just wanted to make sure the OP wasn't solely relying on the TA rules.

And that's what I mean about the rules, for the OP not to interpret 1:1 rules on the ticket/service purchased through CWT vs. AC's fare rules. Although, I do agree in general that fare can be aligned closely between TA and airline.

As an example of my own experiences, in the past, I've purchased tickets and services through TAs where I would pay a lump sum service fee for a year which includes no additional change fees to pay any entity, if done X days in advance, regardless of the airlinre's base fare rules. That's one example. I just wanted to make sure the OP wasn't relying on strictly the TA side of things when at the airport, and not assuming that it was necessarily a true SDC.

If the gist of what I'm saying isn't working, I'll just clarify when we meet in person at a DO. I know there are some here like yourself (?) who are TAs, so I'm just speaking from what I've experienced regarding what penalties or fees I may or may not be charged by my TA vs. If I had bought directly from AC.