You're doing a cost-benefit analysis on a completely arbitrary guess and then using that as the basis for your conclusion? That doesn't work, sorry.
For example, what if in actuality, all other things being equal, they had a 1 in 10 chance focused vs. 1 in 300 chance sanitized, then the results would be 100% chance for the focused versus 33% chance of a response with the sanitized ones. I just used the same thing you did to make the numbers work the other direction.
For the record, based on what I've seen and read, I do think there might be a case for the shotgunned approach, and I personally have had poor luck with the focused approach. But your numbers don't help prove it, sorry.