I'm all for slower progress and mastering technique and not draining your CNS. But I feel that your week 1 and week 4 will be ineffective.
Week 1 is too light. The only sets that will somewhat contribute to stimulating strength gains are the last two, and that will mostly be due to motor learning. There wont be much muscle growth stimulated.
Week 4 is a deload were you don't really need one. Let's face it. Week 1 is super easy, you could do that first thing getting out of bet with hardly a warm-up. Week 2 is still fairly easy being about 10% under what you can handle for all the sets. The only demanding aspect will be the set with 90% and we are talking about only 1 repetition at or above 90% which is hardly a significant stress on the CNS. Week 3 is demanding but only the last set will be somewhat of a challenge/stress. Most people can do 5 reps with 85% if they are on a good day, so 75% for 5 and 80% for 4 aren't that demanding. IMHO there is no need for a deload after essentially 1 fairly demanding week and 2 easy ones.
And I feel like going down that low to deload isn't super effective. There is no need to drop below 60% to deload.