Excel VBA countifs worksheetfunction

I am using WorksheetFunction.CountIfs to count records on Sheet2 depending on certain criteria.

The code I'm using is:

Dim wksdata As Worksheet
Dim xyz as String
Dim Time as String

Set wksdata = Sheets("Data")
Time = Date + TimeValue("08:00:00") 'Set Time value as todays date 8am
Worksheets("Calculations").Range("I15").Value = Time 'set calculations worksheet cell I15 as the time value

Worksheets("Data)").Range("U:U").NumberFormat = "dd/mm/yyyy hh:mm:ss"'converts time column to time format


 xyz = WorksheetFunction.CountIfs(wksdata.Range("I:I"), "xyz", wksdata.Range("K:K"), "C", wksdata.Range("U:U"), "<"& Worksheets("Calculations").Range("I15").Value)

If I change this to work directly in a worksheet (not VBA) then it works with the same logic.

Can anyone point out why it isn't working in VBA and and advice on how to fix it?

Thanks