=IF((COUNTIFS….FORMULA for TIME OVERLAP…ERROR 13 MISMATCH

Hi forum I'm needing some help I have a formula that calculate overlap time

Column A = Student Name
Column B = Time In
Column C = Time Out

Students sometimes sign in/out multiple times hence the reason for the time overlap formula

When I manually put in the formula and drag it down there’s no problem, but when I use my userform vba

ws.Cells(vNewRow, 6).Value =

"=IF((COUNTIFS($A$11:$A$6550,$A$11:$A$6550,$C$11:$C$6550, ">" &$B$11:$B$6550,$B$11:$B$6550,"<"&$C$11:$C$6550 )-1)>0,"OL","")"

I get run-time error '13': type mismatch

The data belonging to the other columns is still transferred but the formula is not transferred to column F

Thank You All