Sometimes the left hand and the right hand don't talk. When the rule came out in 2009, the intro in the Federal Register (74 FR 42516) said,
"Under new § 61.57(c)(4), a person could combine use of the aircraft and FS, FTD, and ATD to obtain instrument experience. When a pilot elects to combine use of an aircraft and simulation device, we will require, under new § 61.57(c)(4), completion of one hour of instrument flight time in the aircraft and three hours in the FS, FTD, or ATD within the preceding 6 calendar months."
Sounds like you have two places to get current, aircraft and "other." Granted, I would have used "or" between FTD and ATD but I think the intent is clear later on. And yet nothing about 1 hour in flight and 3 hours on the ground is in the reg published at the end of that section of FR (74 FR 42550). There have been two technical admendments to 61.57 since 2009 but they were relating to IPCs. Call a FSDO, ask them to explain it to you. They'll most likely scratch their head and call Washington.