xls.parse: fails to skip lines

Hello,
my excel file is like:
- metadata (10 rows)
- header (1 row)
- units (1 row)
- data (250 rows)

Now, I am trying to read it like:

df = xlsall.parse(sheetname='mydata', skiprows=11, header=10)

But it would not assign the information in row 11 as column labels but rather use the units in row 12 (counting from 1).

What could be the cause?
