Manufacturers group their brochures and associated SEER brag based on the highest efficiency of the various combinations in that group of units. Normally there are either 4 or 7 sizes, depending on whether they're 2-stage or 1-stage, 7 being 1-stage. The only exception to the groups is 13-SEER, which is the federal minimum efficiency. Once a unit breaks through the level, all bets are off on what the ACTUAL efficiency is in a GROUP of units. In practice, the larger systems get the lowest SEER/EER/HSPF ratings.
If you're truly interested in the ACTUAL SEER/EER rating of your equipment combination, you have two resources where you can glean that information. The manufacturer has it all as does the AHRI.org. Take your choice.
If YOU want change, YOU have to first change.
If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!