A crucial factor was timing.
As a retaliatory force we would have followed any Soviet attack whereas a premptive attack could be at a time of our choosing.
So, would the Russians plan for TOT in USA during the night? Assuming 2100 start in US it could be 0200 UK (roughly) but how did that accord with exercise 0400 alerts to generate but daytime scrambles a couple of days later?
Having experienced an operational alert on a Friday lunch time and another at 2000 I can attest to which was more difficult and confusing. With an 0400 alert everything ran on rails. For the real deal confusion reigned.