The crystal and roast also don't contribute signicicant fermentables. S-04 is typical of English ale yeasts in that it does not ferment the sugar maltotriose, so even in a typical base malt wort you should only expect ~70% ADF. Mashing lower and longer might have dried it out a bit more, but not much. Looks perfectly normal. Direct pitching at 70° and moving to 60° in the FC is a sound strategy.