"Myrna Larson" wrote...
FWIW, since you refer to the number of function calls, I assume your
concern is with speed. Your proposed formula may be shorter, but if
speed is the issue, arithmetic functions generally beat text/string
functions (plus under-the-hood conversion of text to dates/times).
....

Good point. Wanna time

=A2-A1-(INT(A2/100)-INT(A1/100))*40

?