HC-110 Dilutions

Doing research on Kodak HC-110 it appears that there are various dilution ratios, B D E H etc etc

According to http://www.covingtoninnovations.com/hc110/ he says that dilution H requires roughly twice the developing time as B.

That would mean that for FP4, the development time would be 18 mins. (seems along time to me)?

Whats the advantage of all these different dilutions?

Kodak designed HC-110 to replace several other developers used by commercial processors. These were D-76, DK-50 and DK-60a. The idea being that a processor could move to HC-110 and with the use of an appropriate dilution not have to do anything else. He would not have to change the timings on his processor. For the home user these dilutions provide no real advantages. Stick with a dilution recommended by the film manufacturer. I use 1+49 because it is a metric dilution and thus easy with a lab graduate. Others may use 1+31 or 1+63.

So are you saying that the end result will be the same whether you use 1:31 , 1:63 or 1:49 as an example

Yes if you use the correct development time for each dilution.

Thanks, that makes it even clearer now. I was under the illusion that increasing the dilution say to 1:63 and developing longer could possibly give better results. All these different dilution figures were getting me confused. Just checked Ilford's site and they recommend 9 minutes at dilution B for FP4 which is what I have in the camera at the moment.