i spent some time today at work thinking more about this. i wrote two training plans, one using a 4 week cycle and one using a 3 week cycle over 3 months and compared them.
i will still end up with the exact same training time over that duration, the only difference is that i don't cut back as much for the recovery weeks. but i get one more week of recovery than i would otherwise.
i think your approach makes sense. perhaps i'll try it for my base1 training and see how it feels.