need help with a formula for numbers

Formula for calculating elapsed time in second half tab of Numbers programme

I have this numbers programme I am using. it has 2 tabs one saying first half and the other saying second half. tab first half counts column A is for the actual time. I click on the relevant box in column A and then cell and input the actual time. column b then show says kick off and then every time I click on column a and input the actual time then column B shows the time elapsed between each one. example =

• A4: 10:00:00 (Kick-off - Time only)
• B4: Kick Off
• A5: 10:01:25 (Next Event - Time only) --> B5: 01:25
• A6: 10:10:00 --> B6: 10:00
• A7: 10:45:30 --> B7: 45:30

That all works fine.

My problem is that in my second half tab I want the time to start at 45:00

so A2, I would input the actual time and B2 would say kick off.

so the next time when I click on A3 to input the time it would say ex (4:01:35 or 16:01:35) and then column B3 would say 46:35 and so on and so forth so if my last time input was 4:47:30 the corrosponding column in line B would show as 92:30.

I have tried multiple formulas and can not get this to work.

any help would be appreciated as even open ai says its tried everything and to seek help from apple

[Edited by Moderator]