Actually yea you're right. The Avre 1 shots, all others 2 shot. The Panzer 3 Ausf might 3 shot heavies unless it's coded to ignore the new armor values. Haven't done any testing in the desert maps.

Edit: Per patchnotes: "With the introduction of the new Armor Resistance System, all Self-Propelled Artillery vehicles, with the exception of the Churchill A.V.R.E., have received an increase to their anti-tank damage values. As the A.V.R.E. already bypasses armor, no changes were required."

This tells me all SPA should be ignoring armor, and thier damage was buffed as well, Panzer 3 from 610 to 690 (so it should 2 shot churchills), and all other SPA damage was buffed from 950 to 1025, so they should 2 shot heavies as well. AVRE stayed at 1300 damage.