hi Ray yes you are right there, unlike the Endland and Wales Indexes, the Scottish ones do seem to stop at 1906, i have looked at the Scorrish Register Office site, and it seems like this is because a researcher is able to look at the filmed registers anyway, or pay to have the registers searched, I know this has been a servcie that has been available at the GRO in Scotland for over a decade, but with the Internet and computers, I did think that an index would have been compiled to cover the entries, but I think the value you get for the search fee is far greater than if you had to buy all the English Certificates needed to check an entry, check this link out and see if you agree:
http://www.gro-scotland.gov.uk/famrec/hlpsrch/ leaflet2.html