Houserule: Energy cost multipliers

Here are the energy cost multipliers I use for pumping more energy into a spell in ceremonial casting, and for casting spells on things with a greater SM.  I don't like the simple Regular spell rule of +1 SM = +100%, as that results in things like being able to cast a spell on a battleship for x8 cost, or on the Earth itself for like x47.

The excess energy change is because I had Seekers and Traces being cast at 40+, which tends to make Scrywalls and other countermeasures a joke. Often not that hard for a group of PCs to come up with 80 energy for a single casting of a spell.  I've been thinking about modifying it further and using the same chart for both.

The first one is just the Speed/Range table shifted by a row, and reading "Yards" as "Multipliers."  The second one is the same, with the +20%, +40%, and +60% options added.

Regular Spell Costs for SM > 0

SM	Multiplier
1	x2
2	x3
3	x5
4	x7
5	x10
6	x15
7	x20
8	x30
9	x50
10	x70
11	x100

etc...

Ceremonial Magic Excess Energy Bonus

Energy Cost Multiplier	Bonus
x1.2	+1
x1.4	+2
x1.6	+3
x2	+4
x3	+5
x5	+6
x7	+7
x10	+8
x15	+9
x20	+10
x30	+11
x50	+12
x70	+13
x100	+14

etc...