emoncms.org kWh per day bar graphs off-by-one day

Hi,

I'm converting a real-time solar power output to kilowatt hours per day using the "Power to kWh/d".

I noticed that data produced ends up being out-by-one in the resulting bar graph:

See last week's data from:

http://emoncms.org/vis/auto?feedid=79373

vs

http://emoncms.org/vis/auto?feedid=79374

which is the raw data feed in watts and the kwh/d number.

I was wondering if this was a known bug?  I had a bit of a look through the forum but didn't find anything...

In general, I was wondering if the kwh per day conversion should be avoided, and an absolute kwh counter (i.e. using the Power to kWh) is the better bet?

Cheers,

Tim.