A PCATD cannot be used to meet recency of experience requirements to qualify under 14 CFR 61.57(c).
Advisory Circular AC 61-126, Qualification and Approval of Computer Based Aviation Training Devices
"b. Reducing Flight Hours Through Ground Training. This AC provides for some training time on PCATD's meeting acceptable FAA standards to be used to reduce the total flight hour that otherwise would have to be accomplished in an aircraft or a flight training device to meet the requirement for an instrument rating under part 61 or part 141. PCATD's determined to meet the criteria established by this AC may be used in lieu of, and for not more than, 10 hours of time that ordinarily may be acquired in a flight simulator or flight training device authorized for use under part 61 or part 141. HOWEVER, THE faa HAS NOT AUTHORIZED THE USE OF PCATD'S FOR CONDUCTING PRACTICAL TESTS NOR FOR ACCOMPLISHING RECENCY OF EXPERIENCE REQUIREMENTS. "
A flight instructor can show PCATD time as instruction given. In fact, an instructor is required to do so, by 61.189(a). Note that this requirement isn't stated "should," but "must." Endorsing the logbook to show instruction given is mandatory.
Keeping a log of "total time" that differs from flight time is contradictory, and ill advised.
Advisory Circular AC 61-126, Qualification and Approval of Computer Based Aviation Training Devices
"b. Reducing Flight Hours Through Ground Training. This AC provides for some training time on PCATD's meeting acceptable FAA standards to be used to reduce the total flight hour that otherwise would have to be accomplished in an aircraft or a flight training device to meet the requirement for an instrument rating under part 61 or part 141. PCATD's determined to meet the criteria established by this AC may be used in lieu of, and for not more than, 10 hours of time that ordinarily may be acquired in a flight simulator or flight training device authorized for use under part 61 or part 141. HOWEVER, THE faa HAS NOT AUTHORIZED THE USE OF PCATD'S FOR CONDUCTING PRACTICAL TESTS NOR FOR ACCOMPLISHING RECENCY OF EXPERIENCE REQUIREMENTS. "
A flight instructor can show PCATD time as instruction given. In fact, an instructor is required to do so, by 61.189(a). Note that this requirement isn't stated "should," but "must." Endorsing the logbook to show instruction given is mandatory.
Keeping a log of "total time" that differs from flight time is contradictory, and ill advised.