Reports

I don't seem to be able to reproduce the results, can anyone let me know what I'm missing?
import pandas as pd
import datetime
data = [
    [datetime.datetime(1970, 1, 1, 0, 0), 262.933],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 76923), 261.482],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 153846), 260.394],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 230769), 259.306],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 307692), 258.218],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 384615), 257.311],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 461538), 256.223],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 538461), 255.135],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 615384), 254.047],
    [datetime.datetime(1970, 1, 1, 0, 0, 0, 692307), 253.141],
]
df = pd.DataFrame(data, columns=["timestamp", "x"])
new_date_range = pd.date_range(datetime.datetime(1970, 1, 1, 0, 0), datetime.datetime(1970, 1, 1, 0, 0, 0, 692307), freq="100ms")
df.set_index("timestamp").reindex(new_date_range).interpolate().reset_index()\
# Output as below, but would expect x to vary...
                    index        x
0 1970-01-01 00:00:00.000  262.933
1 1970-01-01 00:00:00.100  262.933
2 1970-01-01 00:00:00.200  262.933
3 1970-01-01 00:00:00.300  262.933
4 1970-01-01 00:00:00.400  262.933
5 1970-01-01 00:00:00.500  262.933
6 1970-01-01 00:00:00.600  262.933
79592366
