Date time punch formua

Assume your table starting from A1 (Header "DATED" at A1).

I am not sure how many rows you have in the worksheet.  If the size is small, try

1. Create a name in Name Manager, Data (Assume 300 records)

   =Sheet1!$A$1:$A$301

2. Select cell A2, create a name in Name Manger, FirstRow

   =AGGREGATE(15,3,MATCH(Data,Sheet1!$A2,0)*ROW(Data),1)

3. Select cell A2, create a name in Name Manger, LastRow

   =AGGREGATE(14,3,MATCH(Data,Sheet1!$A2,0)*ROW(Data),1)

4. Select cell A2, create a name in Name Manger, DateData

   =OFFSET(Sheet1!$A$2, FirstRow - 2, 0, LastRow - FirstRow + 1)

5. Select A2, use the following formula for Conditional Formatting Rule

   =SUMPRODUCT(N(DateData=OFFSET(DateData,1,0)),N(OFFSET(DateData,0,2)<>OFFSET(DateData,1,1)))

6.  Change the Applies To of the CF rule to (Assume 300 records)

   =$A$2:$C$301

 If you have many records, the above approach will be slow.  You may need to use helper columns.

1. In cell D2, type 

   =IF($A1=$A2,$D1,ROW($A2))

2. Copy D2, paste to D3:D301 (Assume 300 records)
3. In cell E2, type

   =IF($A2=$A3,$E3,ROW($A2))

4. Copy E2, paste to E3:E301 (Assume 300 records)
5. Select D2, create a name in Name Manager, DateData2

   =OFFSET(Sheet1!$A$2, Sheet1!$D2-2, 0, Sheet1!$E2-Sheet1!$D2+1)

6. Select A2, use the following formula for Conditional Formatting Rule

   =SUMPRODUCT(N(DateData2=OFFSET(DateData2,1,0)),N(OFFSET(DateData2,0,2)<>OFFSET(DateData2,1,1)))

7.  Change the Applies To of the CF rule to (Assume 300 records)

   =$A$2:$C$301

8.  Hide column D and E