TimeSheet validation problem

[TimMatrix]

I wish to create a "validation entry check" and to work out the hours worked based on a timecard system, in 3 pairs like this: In - Out (Morning); In - Out (Afternoon); In - Out (Extra). (Columns Q-R-S-T-U-V)

Now, sometimes user types in a time on the "wrong" column simply because it was printed on a timecard, this causes time calculations to go astray.

I wanted a formula to reject lines 11,12,14,17,18,21,23 & 24 (see attached) because they're not a complete "pairs" of ins & outs, also at the same time, to calculate the hours worked during the "in-out" periods of any of those three pairs. [The rejection could be highlighted using "conditional formatting" and the total calculation would read "Error" to prevent totalising the weekly hours until rectified.]

I am not sure if I have explained it more clearly but sincerely hope you may be able to understand what I am trying to say...

Much appreciated.

Thanks,

[royUK]

Why post a screenshot? A workbook example would be much more suitable

[TimMatrix]

Okay, I will work some formula out and re-post it here soon. Thanks for fast reply.

[ZERKproject]

see attached,

as you didn't attach a spreadsheet i've placed this in a blank worksheet, see how it works and then modify copy it to your own sheet.