Because I'm functionally retarded, can someone explain to me how the regional seats are awarded?
Basically these add seats in order to make the totals in the region proportional. Proportionality is decided by the regional vote so if a party wins 20% of the regional vote it has to win somewhere around 20% of the seats. Let's say that the region has 10 seats in it, five of which are constituency, and the SNP wins 30% of the vote. That entitles it to 3 of those 10 seats. If the SNP has already won three or more seats they do not get any more seats from the regional list, if they have won less than three seats they recieve however many is needed to achieve the proportional number of seats.
It is basically the same system they use in Germany and is better explained by Wikipedia.
http://en.wikipedia.org/wiki/Mixed_Member_Proportional