Planned, actual and forecast hours

Planned, actual and forecast hours

Hi there, I'm attempting to use Zoho to plan projects and time, but it's so confusing. I have two questions:
  1. Why, in the screen shot below, is my planned hours saying 8? I have assigned 8 work hours to the task, and I have logged 4 hours of actuals. I would expect the planned hours to reduce to 4. This means that my forecast is completely wrong - I'm not forecasting 12 hours for this task, I'm forecasting 8 - 4 of which have been done already. 
  2. At project level, I have two tasks - the one shown above, and then another one (which is non-billable) which has 8 hours planned and 0 hours logged. My project level hours looks like the below, where the hours from the non-billable task seem to have been added to the Forecast but not to the planned, but I would expect that it should show:
    1. Budget 16 hours, as that's what I set
    2. Planned 12 hours (as per logic in question 1)
    3. Actual 4 hours
    4. Difference ???
    5. forecasted 16 hours