Compute lates (in minutes) with the time-logs in a single column

Hi guys, I need some help here. Here's what I want to do...

help.JPG

As you can see here, the time-in and time-out are in the same column. Now, I need to get the total number of minutes late in a cutoff period (say, Oct. 1-15, Minutes late for employee 1 is 250 mins).
- first in, last out (It will ignore accidentally duplicated time-in. If it detects that there are two time-ins on the same date, the second one will be ignored)

I've done something like this in VBA a few weeks ago, but the main difference is, the time-in and time-out are in different columns. So, what I did was to get the time-in of an employee then, check if it's past 8:30AM, if it was, then time-in minus 8:30 = minutes late for that day. Then, I incremented the variable to go to the next row and repeat the same thing and add the result (if late) of that day to the previous one.

The problem I have right now is, on the previous project, I was certain that the next row is another day. On this new project, The next row or the next several rows can be the same day. I just need to get the number of lates for the whole cut-off. The time-outs still matter because they will be used for determining undertime and overtime. But I think I will be able to deal with that later after solving this one first.



Thank you

I badly need help. Noob in programming here...