But it definitely shouldn't cost the same. o_o
Damselfly moves up from 1|1 to 2|1 with a -1 cost.
Improved Mutation moves up from "chance-of-abomination/dying" to "always-mutant" with a +1 cost increase. That means that, even with the -2 from upgrading, Improved Mutation increases its cost by 1, so the effect "always-mutant" costs a 3 more than "chance-of-abomination/dying"
Or, look at it this way:
photon + mutation is 2
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, unupped Guinea Pig costs 1
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1
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.
Ray of Light + Improved Mutation is 3
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, upped Guinea Pig should cost 1
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and 2
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.