can understand your concern , but guess the risk i very low...

the current implementation of execute methode iterates through the meter devices and loades all data (OBIS) from the meter. 
After that i lookup in the items and update the items related to the meter device.

According to your feedback i should iterate through the items of the provider and then create the coresponding meter device.

I choose the current way as multiple items may have point to the same meter device.
A meter device can have multiple OBIS .

I would like to leave it like as is, OK for you?