"The rule was clarified in the last two years. Cones are no longer supposed to be on the actual line if the track was certified without a rail. (Cones on the line ACT as a rail, and thereby lengthen the distance one would travel)"
Who clarified this?
When there is a curb ("Kerb" for everyone on the otherside of the pond), the track is measured 30 cm from the outer edgeof the curb. All other lanes are measured 20 cm from the white line.
When there isn't a curb, the track is measured 20 cm from the white line and cones must be placed on the white line so the outer edge (nearest to the runner) of the cone is in line with the outer edge of the white line.
An easy way to tell if a track was measured with or without a curb:
Measure the distance from the common finish to the stagger (any stagger) in lane 1, then measure the distance from lane 1 stagger to lane 2 stagger - you don't even need a tape measure, you can use a string.
If the staggers are the same then the track was measured without a curb. If they are different, then it was measured with a curb.
Cones should never be used to replace a entire curb. The IAAF allows cones to replace short sections as with the high jump or javelin approaches.
Remember that the white line in all lanes is part of the lane to the runners left.