The MTA does provide for pay protection even if the trip cancels before report, but, like most anything else that favors the pilots, that provision hasn't been fully implemented yet. The protection for sequences that cancel after reporting is an interim step toward full implementation of the MTA.

ackattacker - To your questions, I believe you're correct... you're pay protected for the original value of the 2 2-day trips. The existing protection for LUS pilots on the last trip of the month is not actually the last trip, it's the last series of trips. You could have 5 1-day trips in a row, and they would all be covered by that protection as long as they are the last days of work for the month.