If the problem is the name used when sending to device:
Leading Zeros are important to prevent the 'ASCII Sort' you are seeing.
Code:
{series_index:0>2s}-{title}
the Green part pads the series with leading 0's (change the 2 to a 3 if you will have more than 99 in
ANY series
(you can't change numbering plans in mid use without deleting ALL book in a series from the device and sending them fresh with the new template)
001 Foo
010 Foo
100 Foo
will be the order seen (if sorted by title on the dvice)