Using Ifnull in Subquery SQLite

I've this two tables, members and water_meter

members

id | name
=========
1  | Dani
2  | Dina
3  | Roni

water_meter

id | member_id  | date      | start | finish    | paid  |   paid_at
===+============+===========+=======+===========+=======+=====================+
1  |    1       |2014-07-01 |  12.3 |   38.7    |   1   | 2014-12-29 18:28:30
2  |    2       |2014-07-01 |  57.2 |   64.3    |   0   | null
3  |    3       |2014-07-01 |  14.6 |   52.3    |   0   | null

This member need to pay their water usage every month. What I want is, the 'start' value of each month is the 'finish' value from previous months. This is my query to check water usage at August,

SELECT m.id, m.name, 
ifnull(t.start, (SELECT ifnull(finish, 0) FROM members m2 
LEFT JOIN water_meter t2 ON m2.id = t2.member_id AND t2.date = '2014-07-01') ) as start, 
t.finish, paid
FROM members m 
LEFT JOIN water_meter t ON m.id = t.member_id AND t.date = '2014-08-01'

Result :

id | name   | start  |  finish |
===+========+========+=========+
1  |  Dani  | 38.7   |   null  |
2  |  Dina  | 38.7   |   null  |
3  |  Roni  | 38.7   |   null  |

As you can see, the "start" value is not right. What is the right query for this case?

Check : http://sqlfiddle.com/#!7/29a4c/2