I am curious if this is a bugged item as it states max = 45%?? However, It does not show 45%. The previous aug Anomalous Rock of Alteration shows 15% with Max of 40% and does indeed show to be 40% if you have maximum specialization skill in Alteration.
It adds 15% of your current skill points. So for example if you have 100 skill points you will have 115 with this items. So a Bonus of 15 POINTS. In case you have 300 points the Bonus would be 45 (which is the MAX you can get as Bonus). So from now on, if you have over 300 skill points you will only have that max Bonus of 45.