I like your question because I am wondering the same thing. I tend to want to stick to the training plans no matter what. But as you said maybe these big effort days may help (or they may hinder) your overall progress.
I think the point of the books was to guide us in developing our own training plans specific to each of us, our goal, timeframe etc.
So im curious what the coaches and others have to say about your question as well as what guidelines we should consider when making changes to our training plans.