Okay - PhD level stuff now.
Your TAFB trip gets extended into your next trip which is completely covered by the footprint of the extended trip.

Say there are exactly 24 hours between the trips. That 6.4 CH worth of time between trips is going to be paid at 150% as overage even if you choose SUB. You just don't get any of the overage that occurs after the SUB trip starts.

However - "Overage" is specifically defined in the section 4 BB of the contract and has nothing to do with disruptions (other than they often occur simultaneously). So, my question is:

Without getting into the details of good or bad choices in my example - If you elect SUB and had two extra duty periods and two extra landings on your revised trip that occurred "under" the footprint of the SUB, would you get paid for those? They're not technically "overage", they're disruptions. It seems like you would get paid for those and just give up the true overage pay that falls under the SUB trip footprint, but maybe I'm reading too much into it.