Which American Standard are you actually being quoted?
American Standard sells three real, named tiers: Silver® (entry), Gold® (mid, with two-stage compressors, which run at one of two fixed output levels instead of simply switching on or off), and Platinum® (premium, with variable-speed compressors, which ramp output up and down continuously instead of cycling on and off). Even inside Platinum there's a real step between the 19 and 20 generations. That matters for the numbers used throughout this page, and for the shared-engineering-with-Trane claim above: both apply differently depending on which tier, and which Platinum generation, you're actually being quoted.
Here's what each publishes, straight from American Standard's own materials:
- Silver 16 (entry): up to SEER2 17 / HSPF2 8.5, per American Standard's own product page, essentially tied with Jetson Air's SEER2 17, but behind on HSPF2 9.4.
- Platinum 19 (Side Discharge) (one generation below the flagship): up to SEER2 19.0 / HSPF2 9.0, per American Standard's own heat pump brochure.
- Platinum 20 (flagship): up to SEER2 22.4 and, in a different capacity pairing, up to HSPF2 10.5, no single unit hits both numbers at once, and its published cold-weather data stops at a 5°F test point (more on that below).
American Standard's own consumer product pages don't list an EER2 figure for Silver 16 or Platinum 19 (the federal ENERGY STAR certified-product database does list EER2 for both, just not on American Standard's own marketing pages), and neither tier has any published cold-weather operating floor to compare against Jetson Air's -22°F rating. That's a real gap in what American Standard tells shoppers directly, not an assumption.
It's not a hypothetical concern, either. A Reddit r/heatpumps community spreadsheet of 1,275+ self-reported quotes shows the American Standard model cited most often is 4A6L9024A1000A, a Platinum 19 unit, with Silver 16 showing up regularly too, more often than the Platinum 20 flagship. Jetson only sells one system, so there's no good/better/best ladder to climb the way American Standard's buyers have to. Measured against American Standard's best (Platinum 20), Jetson Air gives up ground on SEER2 and HSPF2 in exchange for a documented, certified cold-weather floor far lower. Measured against Silver and Gold, the entry and mid tiers many homeowners actually end up buying, Jetson Air holds up well on the numbers that are published, and it's the only one of the three with a certified EER2 figure and a certified cold-weather floor at all.

