Hm.
Seems to me there are five factors that should go into the costing of Situational Abilities.
1. The total Refresh cost of abilities that you can use at a time.
2. The list of abilities that you can draw from.
3. How much effort it takes you to change your selection of abilities.
4. The manner in which the GM determines which abilities you get.
5. How much control you have over when your Powers change.
For Eidolon it would be something like...
1. It varies, but always a lot. Like 20+.
2. Pretty much anything.
3. Very little. A supplemental action suffices to swap out an ability. Though it takes a while for the powers to reach full strength.
4. Whatever would be useful in the current situation, with limited input from Eidolon.
5. Quite a bit, but not a full amount. He can usually choose when to change his abilities and he can swap out some without swapping out them all, but sometimes his abilities change on him involuntarily.
For Steve the shaman of the land it would be more like...
1. 4.
2. Sponsored Magics, physical abilities, some Incite Effects, a few other things.
3. Dunno.
4. Whatever suits the area, maybe with some input from Steve.
5. Not a lot. He can hang onto powers until he leaves the area.
So obviously Steve should be spending less Refresh. Not sure how much less, though.
How does that list of factors sound, and do you have any ideas for designing a costing formula?