Following the usual rules for finding which syllable to stress, I find that some words come out sounding a bit improbable:
madefacit, interficit: is the stress really on the second syllable in these words? The third would seem more natural to my (English speaker’s) sense of language.
I believe in madefacere the accent of facere is retained. Hence, madefacit would be pronounced mah’de-FA’cit. This is commonly the case in compounds of facere where the prefix is really a separate word in origin or merely an adverb (e.g. patefacere, malefacere, benefacere, calefacit). Often if the prefix is a true adverb, the adverb is even written separately (as in bene facere).
interficere is another case entirely because it has a true prefix rather than a compounded word. I would expect it to follow normal accentuation rules, but I am not certain. However, it is very rare for the accent in a word of three or more syllables to fall on a short i penult (or any short penult for that matter), as would happen if the third syllable of interficit were accented, and that creates an odd sound to me 
. Assuming it has regular accentuation, interficit would be pronounced in-TER’-fi-cit.
There is very little difference between this and deciding how to pronounce other compound verbs. Is it suf-FI’-cit or SUF’-fi-cit? OB’-(j)i-cit or ob-(J)I’-cit? ad-MO’-net or AD’-mo-net?
Keep in mind that just because something sounds odd to your ears does not necessarily mean that it is wrong, though if something is suspicious or curious it is good to make sure. It took me a while to wrap my head around corporis, corpori, etc being accented on the antepenult. More information for your reading pleasure in Allen & Greenough §12.