If it is a simple linear scale from bottom to top, then Elaida is sitting at a minimum of 82% of Lanfear's strength (if it is a 66 level list).
Egwene would be something like 96% of Moghedien's strength.
The average woman wuld be at 50% of Lanfear's strength, and the average sister at around 55% of Lanfear's strength.
How on earth can we then have Rand easily overpowering Egwene and Elayne - at a time when Egwene states she is already stronger than Moiraine, who on her own is at 82% of Rand's strength?
The examples are endless, but a pure linear scale, with the Forsaken merely occupying the top 12 out o 66 equal levels of strength, doesn't make sense.