NAGs SP Mk2, page-143

Regardless of what they use - lime treatment is still an expensive exercise - and even more expensive at 3 am on a rainy night

from your link dbl:

	LIME A	LIME B
1	Fineness 70, NV 96, $70 per tonne, spreadEffectiveness = (70 x 96)/100 = 67.2Comparative Value = $(70 x 100) / 67.2= $104.15/T	Fineness 99, NV 96, $90 per tonne, spreadEffectiveness = (99 x 96) / 100 = 95.04Comparative Value = $(90 x 100) / 95.04= $94.70/T

This example shows that although Lime A is cheaper than Lime B, because it is less effective, you obtain better value for your money using Lime B.