An apparently modest increase in weight can require machinery changes if the original speed is to be retained. That restarts calculations and makes further changes easier to justify. Alex contrasts this process with the response he attributes to Henderson: keep a useful improvement for the next class or pair of ships. This preserves a buildable current design while continuing development for its successors.
Notable Point · 48:49-50:34
Holding new capital-ship ideas for the next pair
Repeated small additions require fresh weight, speed and machinery calculations and can prevent a design from settling.