I am an Amateur, so (assuming I start the first five races) I have 10 + 20 + a further 10 for starting each race. So for race 1, I would have 40 points available, minus my chassis (17) leaving 23, and so on. However, on the points table after every race I appear to have 10 points less.

I should be able to spend 130 points in total, correct?

Not quite. Amateurs get 20 tokens at the start of the season not 30 (10 +20). I'll correct the season description, the word "additional" makes it a little misleading. However the calculation for a late starter is correct i.e.

*However an "Amateur" driver who fails to start any of the first 5 races will only be eligible for an *~~additional~~ allocation of 10 tokens (rather than 20).So if you start all the races you will earn 10 x 10 = 100 tokens which means you are able to spend 120 tokens in total.

I hope that makes sense, sorry for the confusion.