Not wanting to be argumentative - but the testimony was (and the facts of the testimony were) that all the knives in the knife sets were accounted for.
I believe it's impossible to account for all the knives in a household. Most people have sets, individual knives, left overs from an older set, etc. Plus many will have hunting knives, utility knives as well as knives used for various functions other than cooking / serving - most of which are individual pieces and may not be stored in a kitchen.
It looked like when they laid all the knives out that were in the house, there were only enough to fit in the knife block. You are expecting the jury to believe that he had one knife set and only one extra big, extra sharp knife that was conveniently the one Travis used to cut the rope? That is quite a stretch there. Re: the extra, non-kitchen knives. Well, Travis was not a hunter. If he had other random knives laying around, I might entertain his thought, but I haven't heard anything of the sort. Seems all the knives he had were present and accounted for.