@macuser_22 - you are a forum rockstar. Turbotax support confirmed that it spreads by default and I was able to observe this by going to Tax Tools > Tools > Preview 1040. It shows the amount splint 1/3 from 5a to 5b.
PS - Turbotax support team is excellent. Way above industry average.
PPS - They said if anyone wanted to pay all in one year you'd say at first it was covid disaster related which would wave the 10%, but then say no to the positive test or financial impact questions and theoretically it would allow you to pay it all in one year.
Thanks.
