I have never agreed with the prize chain carrying over into the next month. If you only log in 25 days you should only be able to get to the 25th unit and then start the next chain. However gree has now chosen to make an event out the daily login which is all fine and good but really should have structured it so that everyone was starting off at day 1 instead of making it impossible for people who haven't logged in every day for.... The last 6 months? Some people haven't been able to log in everyday simply because of grees errors and failures of providing support to down accounts which certainly isn't the players fault.
Just my 2 cents