Automated Counter + 24 hour Time Difference.

Dynamic Dropdown + Automated Counter + Time Difference.
I would need help on the following :
Dynamic Dropdown + Automated Counter + Time Difference.

I have attached the file in which I have mentioned the requirements.

1. Dynamic Dropdown :

I have a column mentioning vertical, based on the choice selected in this dropdown in the adjoiing column should display only those values in that drop-down.


2. Automated Counter :

There would be several activities done in a day for a single date, the date is mentioned the column only once so the counter needs to keep a track of the row numbers before it encounters the new date.


3. Time Difference :

The time should work for a 24 hour clock...and not only for 8 hours...(regular shift) The Start time cannot always be less than the End time so if goes in the next day then there arises an error.

Have figured Automatic counter but for Time still require help...

Code :-
IF(AND(ISBLANK(A2),ISBLANK(C2)),"",IF(NOT(ISBLANK(A2)),1,IF(ISBLANK(A2),B1+1,1)))

Please someone help me for the Time Difference...
Things expected are :

1. If I can write 14.30 instead of 14:30 in the Start/end Time and get the difference.

2. If I am working at 19:00 hours and finish my work the next day at 4:00AM early morning ..

Then it would give me an answer of 19:00 to 24:00 = 5 hours + 4 hoyrs = total hours worked 9 hours.

Please find the attachment below for the Automated Counter, others can find this useful..

Dear Noob,

It worked wel but cn u plz explain what happens (G2-F2+(F2>G2))
I didnt understand F2 > G2.... I mean what gets added..