advice on paint shades

Hiya all

I've discovered that finding the correct shades of paint for Russian aircraft can be quite difficult, at least in my neck of the woods. 

I'm currently piecing together an Academy Su27 and need a bit of input re the following:

referring to the shades of blue/grey indicated, I would like to know if there is a mistake.

according to my (relative noob) understanding, Humbrol 89(9)+34(1) means mix 9 parts middle blue with 1 part white.

and

Humbrol 89(7)+34(3) means mix 7 parts middle blue with 3 parts white.

My question is why does the less 'diluted' shade appear lighter in the graphic? Logic dictates the more white involved, the lighter the resulting mix, not so? Should I just swap those 2 around? This could be a totally irrelevant and unimportant question, but it would be nice to begin painting and not realise halfway in that I've made a mistake. I've stripped the paint once already and don' want to do this again...