I've used presoak sometimes, and sometimes not. The results are, for all practical purposes, the same. That's for SS tanks and roll film, or sheet film on a Uniroller base.
Today I skip that step, since I find it unnecessary.
With that said, JoBo processing I believe recommends a 5min prewash, and to me it would make sense if I did tray developing of sheet film. Two bath developers, as mentioned above, makes sense not to prewash.
Then there's also the notion of water quality, where in certain water conditions, washing away the surfactants Ilford uses (PE mentions those) could be detrimental, while with other water qualities it could be beneficial. Think hard/soft water, pH, mineral content, etc.
Do whatever works for you, no worries and don't fix what isn't broken.