Somewhere in WWE (I don't recall the page # and I don't have it in front of me) SWB states something to the effect that this isn't part of Spelling lessons, if the child asks how to spell a word tell them how. The focus in WWE is getting children writing- doing copywork, narration and dictation on their level with constant progression.
So, while I would worry about spelling (and I am having to remediate my 10 yo ds) when doing WWE I wouldn't worry too much about it.
Work on Spelling and WWE as seperate subjects, there will come a time when it will matter more,but for now I'm going with SWB's recommendations.
JMHO, HTH :)