I read a discussion on finding developing times for WEPHOTA NP 22 (4x5"), where some gave this simple method to determine developing times:

I'll brake a pledge of OMETRA and tell you a secret given by American war photographers to Russian war photographers at the end of World War II.HOW TO FIND OUT PROCESSING TIME OF ANY FILM IN ANY DEVELOPER:
1. In a darkroom cut off a few strips 6-8 mm wide from the film you want to develop.
2. Turn the lights on. The strips are fogged now.
3. Take one strip with your right hand and a stopwatch with your left hand.
4. Dip one half of the strip in a developer and start a stop watch. The emulsion side of thefilm strip placed in a developer will start lightening first and then darkening.
5. WHEN THE DARKNESS OF BOTH PARTS OF THE STRIP MATCH STOP THE STOPWATCH!
6. Divide the number of SECONDS shown by the stopwatch by 3. This is your developingtime in MINUTES. If stopwatch shows 24 seconds, developing time is 8 minutes.
7. Repeat two-three times for consistency.
This method never failed for the last 60 years.
(source: http://photo.net/black-and-white-pho...g-forum/00b4nz)

I was wondering: could it really be that simple? Not exact science - I know - but if it works a good method to find a starting point for any unknown film.
Has anyone actually tried this?