I've since discovered that the last argument to this constructor should be changed to **false** if to support cell formula evaluation. In our specific use-case, our file has formulas that only pertain to the current row being processed (eg, C2 = D2 / 2). I'm not sure what happens if a formula were to span multiple rows (eg, C2 = D1 / 2 ). My guess is it wouldn't be supported since only one row of the file is in memory at any given time? Anyways, just FYI. =)