actually--
You seem like a reasonable guy.
We all know that .25 is around what you add now, if you have excellent timers.
Harbig ran in the stone age, with stone age hand timing. I don't remember the guy's name, but some Kinesiology PhD student did a study in the early 1990's to determine just this issue--whether old hand times were any worse than newer hand times.
IIRC, they were substantially worse, up to something like .50-.60
Give me a year, and I will find out if he published, and if so, where.
Also, were those few of Harbig's great times timed by multiple timers, or by just one? If they were by just one, you can probably throw them out.
I have had some amazing hand times myself, but you learn to ignore them. They only sort out the order of finish when something goes wrong with the FAT system.