If you "upgrade" a ticket, essentially you are paying the difference between the price of the ticket you hold and the ticket or pass that you want in the end. So if you upgrade a 6-day base ticket then it isn't something you can save. It's being used towards the cost of the AP. Think of it as a gift card that holds the dollar amount that the original ticket costs. If you upgrade it, you cash in your value of the ticket then pay whatever the additional amount is to get to the price of the AP.
The part about tickets being saveable is if you are in a situation in the future where you have a valid AP and book a free dining package that includes park tickets. Obviously you don't need the tickets if you have an AP to use, right? Well, you can hold onto that never-touched ticket in your package even after you use up your dining credits and go home. As long as you don't touch the ticket it's not going to expire. MYW tickets that don't have the no-expiration option won't expire until 14 days after first use. If you don't use them, they won't expire. That's how my hubby held onto a 10-day base ticket for 8 months before upgrading it to an AP.
How would the saved ticket apply to you? Well, let's say you are on your upcoming free dining trip that has 6-day base tickets for each person in your family of 4. You'd like to get an annual pass for a future trip to be able to book AP discounts, get TiW, and/or utilize other discounts. Maybe upgrading all 4 is a chunk of money you don't want to absorb right now. Well, you are only required to have 1 valid AP to book the AP rates & be eligible for the perks in the future. So, you take just 1 or 2 of your 6-day MYW tickets & upgrade them to APs. The others in your family just use their MYW tickets same as always. Buuuuut, a great free dining offer comes up within your year of your AP. If you book free dining you have to get each person in the room a MYW ticket to be able to get the DDP. The person or persons who have AP's don't need them this trip. THOSE tickets you will not touch. Leave them alone. As long as you don't use them, the expiration clock doesn't start. Now you can either let the non-AP people utilize the MYW tickets on the package or take this opportunity to upgrade them to APs as well. ((The perk to not having your whole family with APs that expire all at the same time is, depending on how you time your trips, you can go without having to buy passes for everyone every time. It makes that ticket portion of the budget a bit more manageable.))
I know it's like mental gymnastics figuring this stuff out. I'll help all I can. As straight-forward as the MYW ticket structure is, there's also a loooot of twists & turns to be explored. :wave: