Best ticket option?

[ElleBelle88]

My DS, husband and their baby are due to go to Orlando three times within the next year (I'm only slightly jealous lol). They will likely visit the Disney parks for a total of 12 days minimum over these three periods and I'm trying to help them with the best value tickets. The options I can see are annual pass, magic my way (4 days x 3) or 14day ultimate and then upgrade. How much is it likely to be to upgrade please? I seem to have read that prices can vary?

Any thoughts/suggestions would be greatly appreciated please.