Building an imprisoned immobile pretender

[Will]

Forrest said:
There must be a ramping effect on build up.

Yes, each level added to magic/dominion above the starting level takes more and more points. For magic, it's level*8 points for each beyond base skill (except for first skill in unknown path, which uses the base path cost). So if you have S1, S2 costs 8, and S3 costs 8+16=24. For dominion, it is 7*level for each beyond base. So if you start with dominion 3, dominion 4 costs 7 additional, dominion 5 costs 7+14=21 additional. So, because the Oracle starts out with S3 instead of S1, and dominion 4 instead of dominion 2, you end up saving a lot when you take those two attributes higher on the Oracle compared to a Divine Emperor. Since you're increasing astral by 8 instead of 6, it costs 56+64=120 points more for that, and increasing dominion by 8 instead of 6, it costs 49+56=105 points more, and the Divine Emperor has a base cost of 35. So it is a difference of 260 points right there. What makes it 230 is that the Oracle has a base path cost of 40, compared to Divine Emperor's 10, which means the Oracle pays 30 more points to start out a Water path.

Check out pp 46-52 of the manual for more details on pretender creation.