I actually did mention caps, albeit briefly, in my rant.
Here is how they helped at the operator where I worked pre 9/11. We had an 85 hour cap. That meant that lines weren't constructed with more than 85 - although many were constructed with less. You would bid and pick up to get as close to 85 as possible. If you went over block and you exceeded 85, the remainder went into a negative bank.
When the bank was sufficient you could cash it out to drop a trip or a piece of a trip. What this allowed me to do was level my earnings. I knew that I would always get 85 credit hours per month. It was nice to be able to drop trips and not have to worry about losing pay (once the bank had some $$ in it).
Not pretending that I understand completely how your old system worked, but it sounds like if you ended up working over 85 hours, you didn't get paid for it, but rather went into a bank that you could tap later to get paid 85 when you actually dropped something to work less. Or you could cash it out at some point. Is that right? If so, personally, I think that particular system only helps the company, in that they hold on to your earned salary for some amount of time before they "give" it to you. It's THEM earning the time-value of YOUR money. Personally, I would hate that; it's worse than overwithholding you taxes, and giving Uncle Sam an interest-free loan. But to each, his own.
How about this: negotiate the same thing without a cap. Call it the same thing if you want--a negative bank. Tell the company you want to defer some of this month's trip credit, and use it (or cash it out) in a later month, for instance for a dropped trip. Why do you have to have a cap to do this? My way has even more flexibility--you can still "bank" earned TFPs for later, if you're so inclined, but you can also work more for more money if you want or need.
I guess I'm just a little different than your average SW pilot. I want to earn a good living, but don't care about getting rich. I want to work as little as possible for as much money as possible. And I'd really like the GO to pay for employee parking, give us an industry standard retirement that doesn't require a match from me, and throw a box lunch at us on the way to that Aruba turn! ;-)
Like I said, I'd like some of that extra stuff, too. But I really want to earn the living that I want, in the fewest work days possible. Plus have the flexibility to earn more in a given month, should I need it for something that comes up.
Bubba