The actual computer system that Disney uses for reservations has a thing it does called "preferencing."
Long story short - it'll recommend what Disney needs over what you asked for.
If booking is sluggish at Port Orleans but the All Stars are running near capacity the system wont offer All stars and will recommend Port Orleans as an alternative, despite there being rooms still at All Stars.. which will become available as Port Orleans books up.
If a phone agent refuses a preference selection and forces the computer to "look again" it'll find the inventory. When you do it at home via the website you dont really get the choice to sidestep it.
That's part 1 of why you get different answers for what's available..
Part 2..
A
travel agent typically isn't working in real time with the reservation systems. They really just end up calling in to the same Reservations number that you called but talking to agents who do transactions for travel agents all day. Same building, same training, etc..
They take what you've requested, calculate how much it should cost, take all your info.. and then call Reservations just like you would. They get some percentage of the amount you book as a kickback for referring you - in theory they could have sent you to Figi I suppose, but we all know it's a cottage industry of travel agents who only book
Disney vacations. Might as well be paid employees of the company.
So that's part 2 of why you got different answers.
And finally.. part 3.. different phone agents will give you different answers on if you can combine codes or "double pins" or what have you. It's not really at their discretion to decide if you can or not.. but moreso along the line sof it they know how to make the computer system accept it or not if it's possible to do.
So, there you have it.