the difference in skeletons obtained by Vidomina with forbidden expert and permitted advanced necromancy is only10%
the difference is more than 10%. it seems you are not taking specialization into account, and that is why there is this whole discussion.
It receives an additional 5% per level to the percentage skill indicator of Spellcasting. The number of raised units (%) is calculated using the formula:
k*(1+0.05*Level),
where k=10 for the basic level of the secondary skill Spellcasting
k=20 for the advanced level
k=30 for the expert level
The maximum significant level of this skill is 100%.