http://web.archive.org/web/200003012325 ... m/mage.htm* Every skill point from the minimum Skill necessary and beyond provides, approximately, an additional 2% to 3% chance of casting Spells of the this Circle, until the maximum of a 99% chance of success is reached. (Circles 1, 7 and 8 do not follow this guideline exactly).
Now, from what I understand..at GM magery on this shard it is 100% sure you will succeed on fourth circles etc.
Now, I have found some weird info on spell casting times, hopefully someone can clear it up for me:
http://web.archive.org/web/200003090417 ... pellsw.htm
http://web.archive.org/web/200003090612 ... pellsn.htm
This can also be listed on all other previous stratics dates throughout T2A, however I am too lazy to post these all so you will either have to take my word for it or check yourselves

Now I understand this doesn't fit the formula posted on stratics, but it is just strange that it is on at least 2 different pages (possibly more) throughout years (you think someone would have noticed, even a viewer?) and after the format was updated as well.
Just something to consider!