I have to agree with outofsynch and MrB.
The intent of an "IFR Actual" column is to log the time spent IMC and not flying under IFR rules and procedures. As such when you enter cloud, and you are Pilot Flying (PF) for that sector, whether the AP is in or not you can log IFR Actual. Obviously a stopwatch does not enter the picture and a common sense estimate of the time is appropriate.
If you are flying for a major airline I am surprised you have not worked this out for yourself yet - perhaps an audit is in order!