Not compatible with release 16 of the ruleset. Features of this extension will be in release 17. Don't use this extension anymore.
It seems like it would be pretty handy in PF2 to have the option of a SPELL LEVEL multiplier for dice in addition to CL, odd CL, and even CL.. maybe HALF Spell Level as well.. although that might be less important.
Spells like Lightning Bolt, Shocking Grasp, and Fireball all have more or less fixed damage for the Spell Level.. but they can often be relatively easily be Heightened to a different Spell Level and do damage based on that Level instead of the CL.
I looked at building an extension for it.. seems like something would need to be done in record_spell_roll.xml, strings_PFRPG2.xml (although this bit could probably be faked in record_spell_roll.xml), and manager_spell.lua.. I'd rather not mess with the last one as it is likely to change fairly often with updates.. but the addition seems fairly straight forward.
Overall this seems like a good suggestion for the ruleset in general as many/most damage dealing spells could make use of this logic.
The EXTENSION
It works very simply, adds another option to the spell damage configuration window for both the DICE and the additional damage. It does this for both DAMAGE and HEALING.