Fix monthly vs daily consumption confusion (again)

Not sure if `consumption` can be an integer here, but if it can I'm wondering if you want integer division?

```python
>>> 29/30
0
>>> 29/30.
0.9666666666666667

# If a floating point result is undesirable consider
>>> int(round(29/30.))
1
```
See http://stackoverflow.com/a/183870/10840 for a better explanation.

Suggested alternative: `return consumption / 30. if ...`