can you just try my exact code with a three + slide presentation open and something in the Excel range. Let's see if that works for you first and then maybe post all your code.

Sub paste_toPPT()
Dim pptApp As PowerPoint.Application
Dim pptPres As PowerPoint.Presentation
Dim myRange As Excel.Range
Set myRange = ActiveSheet.Range("F6:F8")
Set pptApp = GetObject(Class:="PowerPoint.Application")
Set pptPres = pptApp.ActivePresentation
myRange.Copy
pptPres.Windows(1).Activate
pptPres.Windows(1).View.GotoSlide 3
pptApp.CommandBars.ExecuteMso ("PasteSourceFormatting")
End Sub