Is my calculation for tanking artemis missiles correct

An artemis missile costs 80 metal and does 1600 damage
A krow costs 4200 and has 16000 hp.

So an artemis missile on a krow does 1600 damage which is 1/10 of its life. To repair this krow costs 420 energy (4200 * 1/10). So if you have an e/m overdrive ratio above 420/80 ~= 5.25 then tanking artemis hits with a krow is cost efficient, assuming you can repair it afterwards and won't lose it

The missile also costs energy. Also check whether the repair energy is correct.