Pre-LP, which means for scenes shot around 1992-2012, I had applied a minimum of 30secs for a DAP scene to count as full fledged DAP. After 2012 I apply rather a 60sec rule, but I dont count sharply since counting kills the scenes heat. She'd still better dap for at least 1min, though.

DAP-ing starts to count for me as soon as the glans of both penises are inside the girls ass. Up only to the glans this equals tip-fucking ofc, which ideally is avoided. But girls have to start somewhere and most master DAP only later after usually 3-4 DAP scenes.
DAP tagged or DAP billed scenes not meeting these standards are counted as DAPattempts only in my book. A DAPattempt has additionally another set of qualities not easily measurable such as girls intention vs. studs spontaneous trial and supposed or know reasons for stopped attempt. Thus a DAPattempt can well last over 1min.