Your $129 Outer Express bus pass, even though it’s on a CharlieTicket, is good on any bus, subway, streetcar, Zone 1A commuter rail trip, or Inner Harbor Ferry. Take as many rides as you want, transfer as many times as you want, it should work.

You cannot use an $89 Inner Express bus pass plus “the difference in cash” on an Outer Express bus route. Nor can you use a LinkPass or a Local Bus Pass. The T has eliminated all “pay the difference in cash” fares with this month’s fare increase.

Then go get a Charlie Card and put your next monthly pass on it. It can store *both* a pass and some cash value (should you need, say, a bus pass but also an occasional subway ride).
There’s no call for you to have a (paper) Charlie Ticket at all. Then you’ll have a fully replaceable $129 piece of RFID to carry around that can be automatically updated at the first of each month with your new pass. No more going down to the machines or the booths at all. You always pay the cheapest fare, and it’s about 4000x faster and more reliable to board.
Gee, you’d almost think they were stacking the decks to get people to use the thing…

By the by, there’s no magic short-range mothership transmission, there’s simply a timestamp stored on the Charlie Card when you tap it…thus the T is indeed assuring you have the time to get your free transfer by having you tap on the way *out* of long rides.