Workaround for the precision limitation for Python's round() function
Following ferada's advice I looked up the decimal module and it simplifies things quite a bit.

This is a function that does what format_5() does but much succinctly:

def format_5_dec(f):
    new_float = Decimal.quantize(f, Decimal(str(f)[:-1]), rounding='ROUND_UP')
    return new_float