Still works for me... are you sure you don't have any trailing "blanks" or
spaces after the manager names?

I get files all the time from people where they add blank spaces after text
items--drives me insane because you can't do any kind of matching or
lookups.

Make sure "Smith" doesn't have any trailing spaces.

Otherwise, I recreated what you described, and it works for me...

All I meant by Manager1 was a generic name, like Manager2, Manager3,
Manager4, etc...

You might also try the simple case of listing the Manager names in a column,
then in the very next column, without any formulas, enter the "1" or "0",
then try the formula, although I used an IF formula to create a 1 or 0, and
it still worked fine summing on the results of the formula.