The scores are standardised not raw scores. There is an explanation on this site at
http://www.elevenplusexams.co.uk/standa ... scores.php
and it has a link to a fuller explanation by NfER.
The Consortium's new website also has an explanation - see the sticky above.
All the questions in the tests carry equal (raw) marks so a tip for children who find the time pressure hard is to move on from any question which is taking too long to maximise the number of questions they get through (especially for Verbal Reasoning where they do the whole paper at once).