Spring chart - Unsure how accurate?

[Allan1875]

http://www.petitrc.com/setup/yokomo/...ringsChart.pdf

As per the above spring chart, i was a bit dubious about the rates of the kit rear green and front orange as they felt heavier than quoted.

My friend who measures springs checked them and got the following:

Green rear 2.78lbs
Orange front 4.56lbs

That is absolutely miles from the 2.05 and 3.17 quoted on that chart. Even more confusing is my manual states that the kit springs are both blue front and rear?

I am hoping the Yatabe springs on the chart are closer. Anyone else any similar experiences?

I have asked my friend who measured the rating to post his method here as I am sure you may want to analyse it.

EDIT: Could it be that the new kits now come with the Yatabe springs anodised in black as that would be far more accurate? The reason I never gave this any thought previously is that the kit springs are black and the yatabe springs are that bronze colour.